Systems and methods to zero a tile register pair

ABSTRACT

Embodiments detailed herein relate to systems and methods to zero a tile register pair. In one example, a processor includes decode circuitry to decode a matrix pair zeroing instruction having fields for an opcode and an identifier to identify a destination matrix having a PAIR parameter equal to TRUE; and execution circuitry to execute the decoded matrix pair zeroing instruction to zero every element of a left matrix and a right matrix of the identified destination matrix.

FIELD OF INVENTION

The field of invention relates generally to computer processorarchitecture, and, more specifically, to systems and methods to zero atile register pair.

BACKGROUND

Matrices are increasingly important in many computing tasks such asmachine learning and other bulk data processing.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example and notlimitation in the figures of the accompanying drawings, in which likereferences indicate similar elements and in which:

FIG. 1A illustrates an embodiment of configured tiles;

FIG. 1B illustrates an embodiment of configured tiles;

FIG. 2 illustrates several examples of matrix storage;

FIG. 3 illustrates an embodiment of a system utilizing a matrix (tile)operations accelerator;

FIGS. 4 and 5 show different embodiments of how memory is shared using amatrix operations accelerator;

FIG. 6 illustrates an embodiment of matrix multiply accumulate operationusing tiles (“TMMA”);

FIG. 7 illustrates an embodiment of a subset of the execution of aniteration of a chained fused multiply accumulate instruction;

FIG. 8 illustrates an embodiment of a subset of the execution of aniteration of a chained fused multiply accumulate instruction;

FIG. 9 illustrates an embodiment of a subset of the execution of aniteration of a chained fused multiply accumulate instruction;

FIG. 10 illustrates an embodiment of a subset of the execution of aniteration of chained fused multiply accumulate instruction;

FIG. 11 illustrates power-of-two sized SIMD implementations wherein theaccumulators use input sizes that are larger than the inputs to themultipliers according to an embodiment;

FIG. 12 illustrates an embodiment of a system utilizing matrixoperations circuitry;

FIG. 13 illustrates an embodiment of a processor core pipelinesupporting matrix operations using tiles;

FIG. 14 illustrates an embodiment of a processor core pipelinesupporting matrix operations using tiles;

FIG. 15 illustrates an example of a matrix expressed in row major formatand column major format;

FIG. 16 illustrates an example of usage of matrices (tiles);

FIG. 17 illustrates an embodiment a method of usage of matrices (tiles);

FIG. 18 illustrates support for configuration of the usage of tilesaccording to an embodiment;

FIG. 19 illustrates an embodiment of a description of the matrices(tiles) to be supported;

FIGS. 20(A)-(D) illustrate examples of register(s);

FIG. 21 illustrates an exemplary execution of a TZPAIR instruction;

FIG. 22 illustrates an embodiment of method performed by a processor toprocess a TZPAIR instruction;

FIG. 23 illustrates a more detailed description of an execution of aTZPAIR instruction;

FIG. 24 is exemplary pseudocode describing an embodiment of a methodperformed by a processor to process a TZPAIR instruction;

FIGS. 25A-25B are block diagrams illustrating a generic vector friendlyinstruction format and instruction templates thereof according toembodiments of the invention;

FIG. 25A is a block diagram illustrating a generic vector friendlyinstruction format and class A instruction templates thereof accordingto embodiments of the invention;

FIG. 25B is a block diagram illustrating the generic vector friendlyinstruction format and class B instruction templates thereof accordingto embodiments of the invention;

FIG. 26A is a block diagram illustrating an exemplary specific vectorfriendly instruction format according to embodiments of the invention;

FIG. 26B is a block diagram illustrating the fields of the specificvector friendly instruction format that make up the full opcode fieldaccording to one embodiment of the invention;

FIG. 26C is a block diagram illustrating the fields of the specificvector friendly instruction format that make up the register index fieldaccording to one embodiment of the invention;

FIG. 26D is a block diagram illustrating the fields of the specificvector friendly instruction format that make up the augmentationoperation field according to one embodiment of the invention;

FIG. 27 is a block diagram of a register architecture according to oneembodiment of the invention;

FIG. 28A is a block diagram illustrating both an exemplary in-orderpipeline and an exemplary register renaming, out-of-orderissue/execution pipeline according to embodiments of the invention;

FIG. 28B is a block diagram illustrating both an exemplary embodiment ofan in-order architecture core and an exemplary register renaming,out-of-order issue/execution architecture core to be included in aprocessor according to embodiments of the invention;

FIGS. 29A-B illustrate a block diagram of a more specific exemplaryin-order core architecture, which core would be one of several logicblocks (including other cores of the same type and/or different types)in a chip;

FIG. 29A is a block diagram of a single processor core, along with itsconnection to the on-die interconnect network and with its local subsetof the Level 2 (L2) cache, according to embodiments of the invention;

FIG. 29B is an expanded view of part of the processor core in FIG. 29Aaccording to embodiments of the invention;

FIG. 30 is a block diagram of a processor that may have more than onecore, may have an integrated memory controller, and may have integratedgraphics according to embodiments of the invention;

FIGS. 31-34 are block diagrams of exemplary computer architectures;

FIG. 31 shown a block diagram of a system in accordance with oneembodiment of the present invention;

FIG. 32 is a block diagram of a first more specific exemplary system inaccordance with an embodiment of the present invention;

FIG. 33 is a block diagram of a second more specific exemplary system inaccordance with an embodiment of the present invention;

FIG. 34 is a block diagram of a System-on-a-Chip (SoC) in accordancewith an embodiment of the present invention; and

FIG. 35 is a block diagram contrasting the use of a software instructionconverter to convert binary instructions in a source instruction set tobinary instructions in a target instruction set according to embodimentsof the invention.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth.However, it is understood that embodiments of the invention may bepracticed without these specific details. In other instances, well-knowncircuits, structures and techniques have not been shown in detail inorder not to obscure the understanding of this description.

References in the specification to “one embodiment,” “an embodiment,”“an example embodiment,” etc., indicate that the embodiment describedmay include a particular feature, structure, or characteristic, butevery embodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed.

In many mainstream processors, handling matrices is a difficult and/orinstruction intensive task. For example, rows of a matrix could be putinto a plurality of packed data (e.g., SIMD or vector) registers andthen operated on individually. For example, an add two 8×2 matrices mayrequire a load or gather into four packed data registers depending upondata sizes. Then a first add of packed data registers corresponding to afirst row from each matrix is performed and a second add of packed dataregisters corresponding to a second row from each matrix is performed.Then the resulting packed data registers are scattered back to memory.While for small matrices this scenario may be acceptable, it is oftennot acceptable with larger matrices.

I. High-Level Discussion

Described herein are mechanisms to support matrix operations in computerhardware such as central processing units (CPUs), graphic processingunits (GPUs), and accelerators. The matrix operations utilize2-dimensional (2-D) data structures representing one or more packedregions of memory such as registers. Throughout this description, these2-D data structures are referred to as tiles. Note that a matrix may besmaller than a tile (use less than all of a tile), or utilize aplurality of tiles (the matrix is larger than the size of any one tile).Throughout the description, matrix (tile) language is used to indicateoperations performed using tiles that impact a matrix; whether or notthat matrix is larger than any one tile is not typically relevant.

Each tile may be acted upon by different operations such as those thatare detailed herein and include, but are not limited to: matrix (tile)multiplication, tile add, tile subtract, tile diagonal, tile zero, tiletranspose, tile dot product, tile broadcast, tile row broadcast, tilecolumn broadcast, tile multiplication, tile multiplication andaccumulation, tile move, etc. Additionally, support for operators suchas the use of a scale and/or bias may be used with these operations orin support of non-numeric applications in the future, for instance,OpenCL “local memory,” data compression/decompression, etc.

Portions of storage (such as memory (non-volatile and volatile),registers, cache, etc.) are arranged into tiles of different horizontaland vertical dimensions. For example, a tile may have horizontaldimension of 4 (e.g., four rows of a matrix) and a vertical dimension of8 (e.g., 8 columns of the matrix). Typically, the horizontal dimensionis related to element sizes (e.g., 2-, 4-, 8-, 16-, 32-, 64-, 128-bit,etc.). Multiple datatypes (single precision floating point, doubleprecision floating point, integer, etc.) may be supported.

A. Exemplary Usage of Configured Tiles

In some embodiments, tile parameters can be configured. For example, agiven tile may be configured to provide tile options. Exemplary tileoptions include, but are not limited to: a number of rows of the tile, anumber of columns of the tile, whether the tile is VALID, and whetherthe tile consists of a PAIR of equal-sized tiles.

FIG. 1A illustrates an embodiment of configured tiles. As shown, 4 kB ofapplication memory 102 have stored thereon 4 1 kB titles, tile 0 104,tile 1 106, tile 2 108, and tile 3 110. In this example, the 4 tiles donot consist of pairs, and each have elements arranged in rows andcolumns. Tile t0 104 and tile t1 106 have K rows and N columns of 4-byteelements (e.g., single precision data), where K equals 8 and N=32. Tilet2 108 and tile t3 110 have K rows and N/2 columns of 8-byte elements(e.g., double precision data). As the double precision operands aretwice the width of single precision, this configuration is consistentwith a palette, used to provide tile options, supplying at least 4 nameswith total storage of at least 4 kB. In operation, the tiles can beloaded from and stored to memory using load and store operations.Depending upon the instruction encoding scheme used, the amount ofavailable application memory, as well as the size, number, andconfiguration of available tiles varies.

FIG. 1B illustrates an embodiment of configured tiles. As shown, 4 kB ofapplication memory 122 have stored thereon 2 pairs of 1 kB-titles, thefirst pair being tile t4L 124 and tile t4R 126, and the second pairbeing tile t5L 128 and tile t5R 130. As shown the pairs of tiles aredivided into a left tile and a right tile. In other embodiments, thepair of tiles are divided into an even tile and an odd tile. In thisexample, the 4 tiles each have elements arranged in rows and columns.Tile t4L 124 and tile t4R 126 have K rows and N columns of 4-byteelements (e.g., single precision data), where K equals 8 and N equals32. Tile t5L 128 and tile t5R 130 have K rows and N/2 columns of 8-byteelements (e.g., double precision data). As the double precision operandsare twice the width of single precision, this configuration isconsistent with a palette, used to provide tile options, supplying atleast 2 names with total storage of at least 4 kB. The four tiles ofFIG. 1A use 4 names, each naming a 1 kB tile, whereas the 2 pairs oftiles in FIG. 1B can use 2 names to specify the paired tiles. In someembodiments, tile instructions accept a name of a paired tile as anoperand. In operation, the tiles can be loaded from and stored to memoryusing load and store operations. Depending upon the instruction encodingscheme used, the amount of available application memory, as well as thesize, number, and configuration of available tiles varies.

In some embodiments, tile parameters are definable. For example, a“palette” is used to provide tile options. Exemplary options include,but are not limited to: the number of tile names, the number of bytes ina row of storage, the number of rows and columns in a tile, etc. Forexample, a maximum “height” (number of rows) of a tile may be definedas:Tile Max Rows=Architected Storage/(The Number of Palette Names*TheNumber of Bytes per row).

As such, an application can be written such that a fixed usage of nameswill be able to take advantage of different storage sizes acrossimplementations.

Configuration of tiles is done using a tile configuration (“TILECONFIG”)instruction, where a particular tile usage is defined in a selectedpalette. This declaration includes the number of tile names to be used,the requested number of rows and columns per name (tile), and, in someembodiments, the requested datatype of each tile. In some embodiments,consistency checks are performed during the execution of a TILECONFIGinstruction to determine that it matches the restrictions of the paletteentry.

B. Exemplary Tile Storage Types

FIG. 2 illustrates several examples of matrix storage. In (A), a tile isstored in memory. As shown, each “row” consists of four packed dataelements. To get to the next “row,” a stride value is used. Note thatrows may be consecutively stored in memory. Strided memory accessesallows for access of one row to then next when the tile storage does notmap the underlying memory array row width.

Tile loads from memory and stores to memory are typically stridedaccesses from the application memory to packed rows of data. ExemplaryTILELOAD and TILESTORE instructions, or other instruction references toapplication memory as a TILE operand in load-op instructions, are, insome embodiments, restartable to handle (up to) 2*rows of page faults,unmasked floating point exceptions, and/or interrupts per instruction.

In (B), a matrix is stored in a tile comprised of a plurality ofregisters such as packed data registers (single instruction, multipledata (SIMD) or vector registers). In this example, the tile is overlaidon three physical registers. Typically, consecutive registers are used,however, this need not be the case.

In (C), a matrix is stored in a tile in non-register storage accessibleto a fused multiple accumulate (FMA) circuit used in tile operations.This storage may be inside of a FMA, or adjacent to it. Additionally, insome embodiments, discussed below, the storage may be for a data elementand not an entire row or tile.

The supported parameters for the TMMA architecture are reported viaCPUID. In some embodiments, the list of information includes a maximumheight and a maximum SIMD dimension. Configuring the TMMA architecturerequires specifying the dimensions for each tile, the element size foreach tile and the palette identifier. This configuration is done byexecuting the TILECONFIG instruction.

Successful execution of a TILECONFIG instruction enables subsequent TILEoperators. A TILERELEASEALL instruction clears the tile configurationand disables the TILE operations (until the next TILECONFIG instructionsexecutes). In some embodiments, XSAVE, XSTORE, etc. are used in contextswitching using tiles. In some embodiments, 2 XCRO bits are used inXSAVE, one for TILECONFIF metadata and one bit corresponding to actualtile payload data.

TILECONFIG not only configures the tile usage, but also sets a statevariable indicating that the program is in a region of code with tilesconfigured. An implementation may enumerate restrictions on otherinstructions that can be used with a tile region such as no usage of anexisting register set, etc.

Exiting a tile region is typically done with the TILERELEASEALLinstruction. It takes no parameters and swiftly invalidates all tiles(indicating that the data no longer needs any saving or restoring) andclears the internal state corresponding to being in a tile region.

In some embodiments, tile operations will zero any rows and any columnsbeyond the dimensions specified by the tile configuration. For example,tile operations will zero the data beyond the configured number ofcolumns (factoring in the size of the elements) as each row is written.For example, with 64 byte rows and a tile configured with 10 rows and 12columns, an operation writing FP32 elements would write each of thefirst 10 rows with 12*4 bytes with output/result data and zero theremaining 4*4 bytes in each row. Tile operations also fully zero anyrows after the first 10 configured rows. When using 1K tile with 64 byterows, there would be 16 rows, so in this example, the last 6 rows wouldalso be zeroed.

In some embodiments, a context restore (e.g., XRSTOR), when loadingdata, enforces that the data beyond the configured rows for a tile willbe maintained as zero. If there is no valid configuration, all rows arezeroed. XRSTOR of tile data can load garbage in the columns beyond thoseconfigured. It should not be possible for XRSTOR to clear beyond thenumber of columns configured because there is not an element widthassociated with the tile configuration.

Context save (e.g., XSAVE) exposes the entire TILE storage area whenwriting it to memory. If XRSTOR loaded garbage data in to the rightmostpart of a tile, that data will be saved by XSAVE. XSAVE will write zerosfor rows beyond the number specified for each tile.

In some embodiments, tile instructions are restartable. The operationsthat access memory allow restart after page faults. The computationalinstructions that deal with floating point operations also allow forunmasked floating point exceptions, with the masking of the exceptionscontrolled by a control and/or status register.

To support restarting instructions after these events, the instructionsstore information in the start registers detailed below.

II. Matrix (Tile) Operation Systems

A. Exemplary Hardware Support

FIG. 3 illustrates an embodiment of a system utilizing a matrix (tile)operations accelerator. In this illustration, a hostprocessor/processing system 301 communicates commands 311 (e.g., matrixmanipulation operations such as arithmetic or matrix manipulationoperations, or load and store operations) to a matrix operationsaccelerator 307. However, this is shown this way for discussion purposesonly. As detailed later, this accelerator 307 may be a part of aprocessing core. Typically, commands 311 that are tile manipulationoperator instructions will refer to tiles as register-register(“reg-reg”) or register-memory (“reg-mem”) format. Other commands suchas TILESTORE, TILELOAD, TILECONFIG, etc., do not perform data operationson a tile. Commands may be decoded instructions (e.g., micro-ops) ormacro-instructions for the accelerator 307 to handle.

In this example, a coherent memory interface 303 is coupled to the hostprocessor/processing system 301 and matrix operations accelerator 307such that they can share memory. FIGS. 4 and 5 show differentembodiments of how memory is shared using a matrix operationsaccelerator. As shown in FIG. 4, the host processor 401 and matrixoperations accelerator circuitry 405 share the same memory 403. FIG. 5illustrates an embodiment where the host processor 501 and matrixoperations accelerator 505 do not share memory, but can access eachother's memory. For example, processor 501 can access tile memory 507and utilize its host memory 503 as normal. Similarly, the matrixoperations accelerator 505 can access host memory 503, but moretypically uses its own memory 507. Note these memories may be ofdifferent types.

In some embodiments, the matrix operations accelerator 307 includes aplurality of FMAs 309 coupled to data buffers 305 (in someimplementations, one or more of these buffers 305 are stored in the FMAsof the grid as shown). The data buffers 305 buffer tiles loaded frommemory and/or tiles to be stored to memory (e.g., using a tileload ortilestore instruction). Data buffers may be, for example, a plurality ofregisters. Typically, these FMAs are arranged as a grid of chained FMAs309 which are able to read and write tiles. In this example, the matrixoperations accelerator 307 is to perform a matrix multiply operationusing tiles T0, T1, and T2. At least one of tiles is housed in the FMAgrid 309. In some embodiments, all tiles in an operation are stored inthe FMA grid 309. In other embodiments, only a subset is stored in theFMA grid 309. As shown, T1 is housed and T0 and T2 are not. Note that A,B, and C refer to the matrices of these tiles which may or may not takeup the entire space of the tile.

FIG. 6 illustrates an embodiment of matrix multiply accumulate operationusing tiles (“TMMA”).

The number of rows in the matrix (TILE A 601) matches the number ofserial (chained) FMAs comprising the computation's latency. Animplementation is free to recirculate on a grid of smaller height, butthe computation remains the same.

The source/destination vector comes from a tile of N rows (TILE C 605)and the grid of FMAs 611 performs N vector-matrix operations resultingin a complete instruction performing a matrix multiplication of tiles.Tile B 603 is the other vector source and supplies “broadcast” terms tothe FMAs in each stage.

In operation, in some embodiments, the elements of matrix B (stored in atile B 603) are spread across the rectangular grid of FMAs. Matrix B(stored in tile A 601) has its elements of a row transposed to match upwith the columnar dimension of the rectangular grid of FMAs. At each FMAin the grid, an element of A and B are multiplied and added to theincoming summand (from above in the Figure) and the outgoing sum ispassed to the next row of FMAs (or the final output).

The latency of a single step is proportional to K (row height of matrixB) and dependent TMMAs typically have enough source-destination rows(either in a single tile or across tile) to hide that latency. Animplementation may also split the SIMD (packed data element) dimension M(row height of matrix A) across time steps, but this simply changes theconstant that K is multiplied by. When a program specifies a smaller Kthan the maximum enumerated by the TMACC, an implementation is free toimplement this with “masking” or “early outs.”

The latency of an entire TMMA is proportional to N*K. The repeat rate isproportional to N. The number of MACs per TMMA instruction is N*K*M.

FIG. 7 illustrates an embodiment of a subset of the execution of aniteration of a chained fused multiply accumulate instruction. Inparticular, this illustrates execution circuitry of an iteration of onepacked data element position of the destination. In this embodiment, thechained fused multiply accumulate is operating on signed sources whereinthe accumulator is 2× the input data size.

A first signed source (source 1 701) and a second signed source (source2 703) each have four packed data elements. Each of these packed dataelements stores signed data such as floating point data. A third signedsource (source 3 709) has two packed data elements, each of which storessigned data. The sizes of the first and second signed sources 701 and703 are half that of the third signed source (initial value or previousresult) 709. For example, the first and second signed sources 701 and703 could have 32-bit packed data elements (e.g., single precisionfloating point) while the third signed source 709 could have 64-bitpacked data elements (e.g., double precision floating point).

In this illustration, only the two most significant packed data elementpositions of the first and second signed sources 701 and 703 and themost significant packed data element position of the third signed source709 are shown. Of course, the other packed data element positions wouldalso be processed.

As illustrated, packed data elements are processed in pairs. Forexample, the data of the most significant packed data element positionsof the first and second signed sources 701 and 703 are multiplied usinga multiplier circuit 705, and the data from second most significantpacked data element positions of the first and second signed sources 701and 703 are multiplied using a multiplier circuit 707. In someembodiments, these multiplier circuits 705 and 707 are reused for otherpacked data elements positions. In other embodiments, additionalmultiplier circuits are used so that the packed data elements areprocessed in parallel. In some contexts, parallel execution is doneusing lanes that are the size of the signed third source 709. Theresults of each of the multiplications are added using additioncircuitry 711.

The result of the addition of the results of the multiplications isadded to the data from most significant packed data element position ofthe signed source 3 709 (using a different adder 713 or the same adder711).

Finally, the result of the second addition is either stored into thesigned destination 715 in a packed data element position thatcorresponds to the packed data element position used from the signedthird source 709, or passed on to the next iteration, if there is one.In some embodiments, a writemask is applied to this storage such that ifa corresponding writemask (bit) is set, the storage happens, and, if notset, the storage does not happen.

FIG. 8 illustrates an embodiment of a subset of the execution of aniteration of a chained fused multiply accumulate instruction. Inparticular, this illustrates execution circuitry of an iteration of onepacked data element position of the destination. In this embodiment, thechained fused multiply accumulate is operating on signed sources whereinthe accumulator is 2× the input data size.

A first signed source (source 1 801) and a second signed source (source2 803) each have four packed data elements. Each of these packed dataelements stores signed data such as integer data. A third signed source(source 3 809) has two packed data elements, each of which stores signeddata. The sizes of the first and second signed sources 801 and 803 arehalf that of the third signed source 809. For example, the first andsecond signed sources 801 and 803 could have 32-bit packed data elements(e.g., single precision floating point) the third signed source 809could have 64-bit packed data elements (e.g., double precision floatingpoint).

In this illustration, only the two most significant packed data elementpositions of the first and second signed sources 801 and 803 and themost significant packed data element position of the third signed source809 are shown. Of course, the other packed data element positions wouldalso be processed.

As illustrated, packed data elements are processed in pairs. Forexample, the data of the most significant packed data element positionsof the first and second signed sources 801 and 803 are multiplied usinga multiplier circuit 805, and the data from second most significantpacked data element positions of the first and second signed sources 801and 803 are multiplied using a multiplier circuit 807. In someembodiments, these multiplier circuits 805 and 807 are reused for otherpacked data elements positions. In other embodiments, additionalmultiplier circuits are used so that the packed data elements areprocessed in parallel. In some contexts, parallel execution is doneusing lanes that are the size of the signed third source (initial valueor previous iteration result) 809. The results of each of themultiplications are added to the signed third source 809 usingaddition/saturation circuitry 813.

Addition/saturation (accumulator) circuitry 813 preserves a sign of anoperand when the addition results in a value that is too big. Inparticular, saturation evaluation occurs on the infinite precisionresult between the multi-way-add and the write to the destination ornext iteration. When the accumulator 813 is floating point and the inputterms are integer, the sum of products and the floating pointaccumulator input value are turned into infinite precision values (fixedpoint numbers of hundreds of bits), the addition of the multiplicationresults and the third input is performed, and a single rounding to theactual accumulator type is performed.

Unsigned saturation means the output values are limited to a maximumunsigned number for that element width (all 1s). Signed saturation meansa value is limited to the be in the range between a minimum negativenumber and a max positive number for that element width (for bytes forexample, the range is from −128 (=−2{circumflex over ( )}7) to127(=2{circumflex over ( )}7−1)).

The result of the addition and saturation check is stored into thesigned result 815 in a packed data element position that corresponds tothe packed data element position used from the signed third source 809,or passed on to the next iteration if there is one. In some embodiments,a writemask is applied to this storage such that if a correspondingwritemask (bit) is set, the storage happens, and, if not set, thestorage does not happen.

FIG. 9 illustrates an embodiment of a subset of the execution of aniteration of a chained fused multiply accumulate instruction. Inparticular, this illustrates execution circuitry of an iteration of onepacked data element position of the destination. In this embodiment, thechained fused multiply accumulate is operating on a signed source and anunsigned source wherein the accumulator is 4× the input data size.

A first signed source (source 1 901) and a second unsigned source(source 2 903) each have four packed data elements. Each of these packeddata elements has data such as floating point or integer data. A thirdsigned source (initial value or result 915) has a packed data element ofwhich stores signed data. The sizes of the first and second sources 901and 903 are a quarter of the third signed source 915. For example, thefirst and second sources 901 and 903 could have 16-bit packed dataelements (e.g., word) and the third signed source 915 could have 64-bitpacked data elements (e.g., double precision floating point or 64-bitinteger).

In this illustration, the four most significant packed data elementpositions of the first and second sources 901 and 903 and the mostsignificant packed data element position of the third signed source 915are shown. Of course, other packed data element positions would also beprocessed if there are any.

As illustrated, packed data elements are processed in quadruplets. Forexample, the data of the most significant packed data element positionsof the first and second sources 901 and 903 are multiplied using amultiplier circuit 905, data from second most significant packed dataelement positions of the first and second sources 901 and 903 aremultiplied using a multiplier circuit 907, data from third mostsignificant packed data element positions of the first and secondsources 901 and 903 are multiplied using a multiplier circuit 909, anddata from the least significant packed data element positions of thefirst and second sources 901 and 903 are multiplied using a multipliercircuit 911. In some embodiments, the signed packed data elements of thefirst source 901 are sign extended and the unsigned packed data elementsof the second source 903 are zero extended prior to the multiplications.

In some embodiments, these multiplier circuits 905-911 are reused forother packed data elements positions. In other embodiments, additionalmultiplier circuits are used so that the packed data elements areprocessed in parallel. In some contexts, parallel execution is doneusing lanes that are the size of the signed third source 915. Theresults of each of the multiplications are added using additioncircuitry 911.

The result of the addition of the results of the multiplications isadded to the data from most significant packed data element position ofthe signed source 3 915 (using a different adder 913 or the same adder911).

Finally, the result 919 of the second addition is either stored into thesigned destination in a packed data element position that corresponds tothe packed data element position used from the signed third source 915,or passed to the next iteration. In some embodiments, a writemask isapplied to this storage such that if a corresponding writemask (bit) isset, the storage happens, and, if not set, the storage does not happen.

FIG. 10 illustrates an embodiment of a subset of the execution of aniteration of chained fused multiply accumulate instruction. Inparticular, this illustrates execution circuitry of an iteration of onepacked data element position of the destination. In this embodiment, thechained fused multiply accumulate is operating on a signed source and anunsigned source wherein the accumulator is 4× the input data size.

A first signed source (source 1 1001) and a second unsigned source(source 2 1003) each have four packed data elements. Each of thesepacked data elements stores data such as floating point or integer data.A third signed source (initial or previous result 1015) has a packeddata element of which stores signed data. The sizes of the first andsecond sources 1001 and 1003 are a quarter of the third signed source1015. For example, the first and second sources 1001 and 1003 could have16-bit packed data elements (e.g., word) and the third signed source1015 could have 64-bit packed data elements (e.g., double precisionfloating point or 64-bit integer).

In this illustration, the four most significant packed data elementpositions of the first and second sources 1001 and 1003 and the mostsignificant packed data element position of the third signed source 1015are shown. Of course, other packed data element positions would also beprocessed if there are any.

As illustrated, packed data elements are processed in quadruplets. Forexample, the data of the most significant packed data element positionsof the first and second sources 1001 and 1003 are multiplied using amultiplier circuit 1005, data from second most significant packed dataelement positions of the first and second sources 1001 and 1003 aremultiplied using a multiplier circuit 1007, data from third mostsignificant packed data element positions of the first and secondsources 1001 and 1003 are multiplied using a multiplier circuit 1009,and data from the least significant packed data element positions of thefirst and second sources 1001 and 1003 are multiplied using a multipliercircuit 1011. In some embodiments, the signed packed data elements ofthe first source 1001 are sign extended and the unsigned packed dataelements of the second source 1003 are zero extended prior to themultiplications.

In some embodiments, these multiplier circuits 1005-1011 are reused forother packed data elements positions. In other embodiments, additionalmultiplier circuits are used so that the packed data elements areprocessed in parallel. In some contexts, parallel execution is doneusing lanes that are the size of the signed third source 1015. Theresult of the addition of the results of the multiplications is added tothe data from most significant packed data element position of thesigned source 3 1015 using addition/saturation circuitry 1013.

Addition/saturation (accumulator) circuitry 1013 preserves a sign of anoperand when the addition results in a value that is too big or toosmall for signed saturation. In particular, saturation evaluation occurson the infinite precision result between the multi-way-add and the writeto the destination. When the accumulator 1013 is floating point and theinput terms are integer, the sum of products and the floating pointaccumulator input value are turned into infinite precision values (fixedpoint numbers of hundreds of bits), the addition of the multiplicationresults and the third input is performed, and a single rounding to theactual accumulator type is performed.

The result 1019 of the addition and saturation check is stored into thesigned destination in a packed data element position that corresponds tothe packed data element position used from the signed third source 1015,or passed to the next iteration. In some embodiments, a writemask isapplied to this storage such that if a corresponding writemask (bit) isset, the storage happens, and, if not set, the storage does not happen.

FIG. 11 illustrates power-of-two sized SIMD implementations wherein theaccumulators use input sizes that are larger than the inputs to themultipliers according to an embodiment. Note the source (to themultipliers) and accumulator values may be signed or unsigned values.For an accumulator having 2× input sizes (in other words, theaccumulator input value is twice the size of the packed data elementsizes of the sources), table 1101 illustrates different configurations.For byte sized sources, the accumulator uses word or half-precisionfloating-point (HPFP) values that are 16-bit in size. For word sizedsources, the accumulator uses 32-bit integer or single-precisionfloating-point (SPFP) values that are 32-bit in size. For SPFP or 32-bitinteger sized sources, the accumulator uses 64-integer ordouble-precision floating-point (DPFP) values that are 64-bit in size.

For an accumulator having 4× input sizes (in other words, theaccumulator input value is four times the size of the packed dataelement sizes of the sources), table 1103 illustrates differentconfigurations. For byte sized sources, the accumulator uses 32-bitinteger or single-precision floating-point (SPFP) values that are 32-bitin size. For word sized sources, the accumulator uses 64-bit integer ordouble-precision floating-point (DPFP) values that are 64-bit in size insome embodiments.

For an accumulator having 8× input sizes (in other words, theaccumulator input value is eight times the size of the packed dataelement sizes of the sources), table 1105 illustrates a configuration.For byte sized sources, the accumulator uses 64-bit integer.

As hinted at earlier, matrix operations circuitry may be included in acore, or as an external accelerator. FIG. 12 illustrates an embodimentof a system utilizing matrix operations circuitry. In this illustration,a plurality of entities are coupled with a ring interconnect 1245.

A plurality of cores 1201, 1203, 1205, and 1207 provide non-tile basedinstruction support. In some embodiments, matrix operations circuitry1251 is provided in a core 1203, and in other embodiments matrixoperations circuitry 1211 and 1213 are accessible on the ringinterconnect 1245.

Additionally, one or more memory controllers 1223-1225 are provided tocommunicate with memory 1233 and 1231 on behalf of the cores and/ormatrix operations circuitry.

FIG. 13 illustrates an embodiment of a processor core pipelinesupporting matrix operations using tiles. Branch prediction and decodecircuitry 1303 performs branch predicting of instructions, decoding ofinstructions, and/or both from instructions stored in instructionstorage 1301. For example, instructions detailed herein may be stored ininstruction storage. In some implementations, separate circuitry is usedfor branch prediction and in some embodiments, at least someinstructions are decoded into one or more micro-operations, micro-codeentry points, microinstructions, other instructions, or other controlsignals using microcode 1305. The branch prediction and decode circuitry1303 may be implemented using various different mechanisms. Examples ofsuitable mechanisms include, but are not limited to, look-up tables,hardware implementations, programmable logic arrays (PLAs), microcoderead only memories (ROMs), etc.

The branch prediction and decode circuitry 1303 is coupled to arename/allocator circuitry 1307 which is coupled, in some embodiments,to scheduler circuitry 1309. In some embodiments, these circuits provideregister renaming, register allocation, and/or scheduling functionalityby performing one or more of: 1) renaming logical operand values tophysical operand values (e.g., a register alias table in someembodiments), 2) allocating status bits and flags to the decodedinstruction, and 3) scheduling the decoded instruction for execution onexecution circuitry out of an instruction pool (e.g., using areservation station in some embodiments).

The scheduler circuitry 1309 represents any number of differentschedulers, including reservations stations, central instruction window,etc. The scheduler unit(s) scheduler circuitry 1309 is coupled to, orincludes, physical register file(s) 1315. Each of the physical registerfile(s) 1315 represents one or more physical register files, differentones of which store one or more different data types, such as scalarinteger, scalar floating point, packed integer, packed floating point,vector integer, vector floating point, status (e.g., an instructionpointer that is the address of the next instruction to be executed),tiles, etc. In one embodiment, the physical register file(s) 1315comprises vector registers circuitry, write mask registers circuitry,and scalar registers circuitry. These register circuits may providearchitectural vector registers, vector mask registers, and generalpurpose registers. The physical register file(s) 1315 is overlapped by aretirement circuit 1317 to illustrate various ways in which registerrenaming and out-of-order execution may be implemented (e.g., using areorder buffer(s) and a retirement register file(s); using a futurefile(s), a history buffer(s), and a retirement register file(s); using aregister maps and a pool of registers; etc.). The retirement circuit1317 and the physical register file(s) 1315 are coupled to the executioncircuit(s) 1311.

While register renaming is described in the context of out-of-orderexecution, it should be understood that register renaming may be used inan in-order architecture. While the illustrated embodiment of theprocessor may also include separate instruction and data cache units anda shared L2 cache unit, alternative embodiments may have a singleinternal cache for both instructions and data, such as, for example, aLevel 1 (L1) internal cache, or multiple levels of internal cache. Insome embodiments, the system may include a combination of an internalcache and an external cache that is external to the core and/or theprocessor. Alternatively, all of the cache may be external to the coreand/or the processor.

The execution circuitry 1311 a set of one or more execution circuits1321, 1323, and 1327 and a set of one or more memory access circuits1325. The execution circuits 1321, 1323, and 1327 perform variousoperations (e.g., shifts, addition, subtraction, multiplication) and onvarious types of data (e.g., scalar floating point, packed integer,packed floating point, vector integer, vector floating point). Whilesome embodiments may include a number of execution units dedicated tospecific functions or sets of functions, other embodiments may includeonly one execution unit or multiple execution units that all perform allfunctions. The scalar circuitry 1321 performs scalar operations, thevector/SIMD circuitry 1323 performs vector/SIMD operations, and matrixoperations circuitry 1327 performs matrix (tile) operations detailedherein.

By way of example, the exemplary register renaming, out-of-orderissue/execution core architecture may implement a pipeline asfollows: 1) an instruction fetch circuit performs fetch and lengthdecoding stages; 2) the branch and decode circuitry 1303 performs adecode stage; 3) the rename/allocator circuitry 1307 performs anallocation stage and renaming stage; 4) the scheduler circuitry 1309performs a schedule stage; 5) physical register file(s) (coupled to, orincluded in, the scheduler circuitry 1309 and rename/allocate circuitry1307 and a memory unit perform a register read/memory read stage; theexecution circuitry 1311 performs an execute stage; 6) a memory unit andthe physical register file(s) unit(s) perform a write back/memory writestage; 7) various units may be involved in the exception handling stage;and 8) a retirement unit and the physical register file(s) unit(s)perform a commit stage.

The core may support one or more instructions sets (e.g., the x86instruction set (with some extensions that have been added with newerversions); the MIPS instruction set of MIPS Technologies of Sunnyvale,Calif.; the ARM instruction set (with optional additional extensionssuch as NEON) of ARM Holdings of Sunnyvale, Calif.), including theinstruction(s) described herein. In one embodiment, the core 1390includes logic to support a packed data instruction set extension (e.g.,AVX1, AVX2), thereby allowing the operations used by many multimediaapplications to be performed using packed data.

It should be understood that the core may support multithreading(executing two or more parallel sets of operations or threads), and maydo so in a variety of ways including time sliced multithreading,simultaneous multithreading (where a single physical core provides alogical core for each of the threads that physical core issimultaneously multithreading), or a combination thereof (e.g., timesliced fetching and decoding and simultaneous multithreading thereaftersuch as in the Intel® Hyperthreading technology).

FIG. 14 illustrates an embodiment of a processor core pipelinesupporting matrix operations using tiles. Branch prediction and decodecircuitry 1403 performs branch predicting of instructions, decoding ofinstructions, and/or both from instructions stored in instructionstorage 1401. For example, instructions detailed herein may be stored ininstruction storage. In some implementations, separate circuitry is usedfor branch prediction and in some embodiments, at least someinstructions are decoded into one or more micro-operations, micro-codeentry points, microinstructions, other instructions, or other controlsignals using microcode 1405. The branch prediction and decode circuitry1403 may be implemented using various different mechanisms. Examples ofsuitable mechanisms include, but are not limited to, look-up tables,hardware implementations, programmable logic arrays (PLAs), microcoderead only memories (ROMs), etc.

The branch prediction and decode circuitry 1403 is coupled to arename/allocator circuitry 1407 which is coupled, in some embodiments,to scheduler circuitry 1409. In some embodiments, these circuits provideregister renaming, register allocation, and/or scheduling functionalityby performing one or more of: 1) renaming logical operand values tophysical operand values (e.g., a register alias table in someembodiments), 2) allocating status bits and flags to the decodedinstruction, and 3) scheduling the decoded instruction for execution onexecution circuitry out of an instruction pool (e.g., using areservation station in some embodiments).

The scheduler circuitry 1409 represents any number of differentschedulers, including reservations stations, central instruction window,etc. The scheduler unit(s) scheduler circuitry 1409 is coupled to, orincludes, physical register file(s) 1415. Each of the physical registerfile(s) 1415 represents one or more physical register files, differentones of which store one or more different data types, such as scalarinteger, scalar floating point, packed integer, packed floating point,vector integer, vector floating point, status (e.g., an instructionpointer that is the address of the next instruction to be executed),tiles, etc. In one embodiment, the physical register file(s) 1415comprises vector registers circuitry, write mask registers circuitry,and scalar registers circuitry. These register circuits may providearchitectural vector registers, vector mask registers, and generalpurpose registers. The physical register file(s) 1415 is overlapped by aretirement circuit 1417 to illustrate various ways in which registerrenaming and out-of-order execution may be implemented (e.g., using areorder buffer(s) and a retirement register file(s); using a futurefile(s), a history buffer(s), and a retirement register file(s); using aregister maps and a pool of registers; etc.). The retirement circuit1417 and the physical register file(s) 1415 are coupled to the executioncircuit(s) 1411.

While register renaming is described in the context of out-of-orderexecution, it should be understood that register renaming may be used inan in-order architecture. While the illustrated embodiment of theprocessor may also include separate instruction and data cache units anda shared L2 cache unit, alternative embodiments may have a singleinternal cache for both instructions and data, such as, for example, aLevel 1 (L1) internal cache, or multiple levels of internal cache. Insome embodiments, the system may include a combination of an internalcache and an external cache that is external to the core and/or theprocessor. Alternatively, all of the cache may be external to the coreand/or the processor.

The execution circuitry 1411 a set of one or more execution circuits1427 and a set of one or more memory access circuits 1425. The executioncircuits 1427 perform matrix (tile) operations detailed herein.

By way of example, the exemplary register renaming, out-of-orderissue/execution core architecture may implement a pipeline asfollows: 1) an instruction fetch circuit performs fetch and lengthdecoding stages; 2) the branch and decode circuitry 1403 performs adecode stage; 3) the rename/allocator circuitry 1407 performs anallocation stage and renaming stage; 4) the scheduler circuitry 1409performs a schedule stage; 5) physical register file(s) (coupled to, orincluded in, the scheduler circuitry 1407 and rename/allocate circuitry1407 and a memory unit perform a register read/memory read stage; theexecution circuitry 1411 performs an execute stage; 6) a memory unit andthe physical register file(s) unit(s) perform a write back/memory writestage; 7) various units may be involved in the exception handling stage;and 8) a retirement unit and the physical register file(s) unit(s)perform a commit stage.

The core may support one or more instructions sets (e.g., the x86instruction set (with some extensions that have been added with newerversions); the MIPS instruction set of MIPS Technologies of Sunnyvale,Calif.; the ARM instruction set (with optional additional extensionssuch as NEON) of ARM Holdings of Sunnyvale, Calif.), including theinstruction(s) described herein. In one embodiment, the core 1490includes logic to support a packed data instruction set extension (e.g.,AVX1, AVX2), thereby allowing the operations used by many multimediaapplications to be performed using packed data.

It should be understood that the core may support multithreading(executing two or more parallel sets of operations or threads), and maydo so in a variety of ways including time sliced multithreading,simultaneous multithreading (where a single physical core provides alogical core for each of the threads that physical core issimultaneously multithreading), or a combination thereof (e.g., timesliced fetching and decoding and simultaneous multithreading thereaftersuch as in the Intel® Hyperthreading technology).

B. Layout

Throughout this description, data is expressed using row major datalayout. Column major users should translate the terms according to theirorientation. FIG. 15 illustrates an example of a matrix expressed in rowmajor format and column major format. As shown, matrix A is a 2×3matrix. When this matrix is stored in row major format, the dataelements of a row are consecutive. When this matrix is stored in columnmajor format, the data elements of a column are consecutive. It is awell-known property of matrices that A^(T)*B^(T)=(BA)^(T), wheresuperscript T means transpose. Reading column major data as row majordata results in the matrix looking like the transpose matrix.

In some embodiments, row-major semantics are utilized in hardware, andcolumn major data is to swap the operand order with the result beingtransposes of matrix, but for subsequent column-major reads from memoryit is the correct, non-transposed matrix.

For example, if there are two column-major matrices to multiply:

$\begin{matrix}{ab} & {gik} & {{ag} + {{bh}\mspace{14mu}{ai}} + {{bj}\mspace{14mu}{ak}} + {bl}} \\{cd}^{*} & {{hjl} =} & {{cg} + {{dh}\mspace{14mu}{ci}} + {{dj}\mspace{14mu}{ck}} + {dl}} \\{ef} & \; & {{eg} + {{fh}\mspace{14mu}{ei}} + {{fj}\mspace{14mu}{ek}} + {fl}} \\\left( {3 \times 2} \right) & \left( {2 \times 3} \right) & \left( {3 \times 3} \right)\end{matrix}$

The input matrices would be stored in linear memory (column-major) as:

acebdf

and

ghijkl.

Reading those matrices as row-major with dimensions 2×3 and 3×2, theywould appear as:

a c e and g h b d f i j k l

Swapping the order and matrix multiplying:

$\begin{matrix}{gh} & {ace} & {{ag} + {{bh}\mspace{14mu}{cg}} + {{dh}\mspace{14mu}{eg}} + {fh}} \\{ij}^{*} & {{bdf} =} & {{ai} + {{bj}\mspace{14mu}{ci}} + {{dj}\mspace{14mu}{ei}} + {fj}} \\{kl} & \; & {{ak} + {{bl}\mspace{14mu}{ck}} + {{dl}\mspace{14mu}{ek}} + {fl}}\end{matrix}$the transpose matrix is out and can then be stored in in row-majororder:

ag + bh cg + dh eg + fh ai + bj ci + dj ei + fj ak + bl ck + dl ek + fl

and used in subsequent column major computations, it is the correctun-transposed matrix:

ag + bh ai + bj ak + bl cg + dh ci + dj ck + dl eg + fh ei + fj ek + fl

III. Exemplary Usage

FIG. 16 illustrates an example of usage of matrices (tiles). In thisexample, matrix C 1601 includes two tiles, matrix A 1603 includes onetile, and matrix B 1605 includes two tiles. This figure shows an exampleof the inner loop of an algorithm to compute a matrix multiplication. Inthis example, two result tiles, tmm0 and tmm1, from matrix C 1601 areused to accumulate the intermediate results. One tile from the A matrix1603 (tmm2) is re-used twice as it multiplied by two tiles from the Bmatrix 1605. Pointers to load a new A tile and two new B tiles from thedirections indicated by the arrows. An outer loop, not shown, adjuststhe pointers for the C tiles.

The exemplary code as shown includes the usage of a tile configurationinstruction and is executed to configure tile usage, load tiles, a loopto process the tiles, store tiles to memory, and release tile usage.

FIG. 17 illustrates an embodiment of usage of matrices (tiles). At 1701,tile usage is configured. For example, a TILECONFIG instruction isexecuted to configure tile usage including setting a number of rows andcolumns per tile. Typically, at least one matrix (tile) is loaded frommemory at 1703. At least one matrix (tile) operation is performed at1705 using the matrices (tiles). At 1707, at least one matrix (tile) isstored out to memory and a context switch can occur at 1709.

IV. Exemplary Configuration

A. Tile Configuration Hardware Support

As discussed above, tile usage typically needs to be configured prior touse. For example, full usage of all rows and columns may not be needed.Not only does not configuring these rows and columns save power in someembodiments, but the configuration may be used to determine if anoperation will generate an error. For example, a matrix multiplicationof the form (N×M)*(L*N) will typically not work if M and L are not thesame.

Prior to using matrices using tiles, in some embodiments, tile supportis to be configured. For example, how many rows and columns per tile,tiles that are to be used, etc. are configured. A TILECONFIG instructionis an improvement to a computer itself as it provides for support toconfigure the computer to use a matrix accelerator (either as a part ofa processor core, or as an external device). In particular, an executionof the TILECONFIG instruction causes a configuration to be retrievedfrom memory and applied to matrix (tile) settings within a matrixaccelerator.

i. Tile Usage Configuration

FIG. 18 illustrates support for configuration of the usage of tilesaccording to an embodiment. A memory 1801 contains the description ofthe matrices (tiles) to be supported 1803.

Execution circuitry 1811 of a processor/core 1805 stores aspects of atile description 1803 into tile configurations 1817. The tileconfigurations 1817 detail what tiles for a palette are configured (thenumber of rows and columns in each tile) and a marking that matrixsupport is in use. In particular, instruction execution resources 1811are configured to use tiles as specified by the tile configuration 1817.The instruction execution resources may also include a machine specificregister or configuration register to indicate tile usage. Additionalvalues such as in-use and start values are also set. The tileconfigurations 1817 utilize one or more registers 1819 to store tileusage and configuration information.

FIG. 19 illustrates an embodiment of a description of the matrices(tiles) to be supported. This is the description that is to be storedupon an execution of a STTILECFG instruction. In this example, eachfield is a byte. In byte[0], a palette ID 1901 is stored. The palette IDis used to index a palette table 1813 which stores, per palette ID, anumber of bytes in a tile, and bytes per row of the tiles that areassociated with this ID as defined by the configuration.

Byte 1 stores a value to be stored in a “startRow” register 1903 andbyte 2 stores a value to be stored in a “startP” register 1905. Tosupport restarting instructions after these events, the instructionsstore information these registers. To support restarting instructionsafter break events such as those detailed above, the instructions storeinformation in these registers. The startRow value indicates the rowthat should be used for restart. The startP value indicates the positionwithin the row for store operations when pairs are used and, in someembodiments, indicates the lower half of the row (in the lower tile of apair) or higher half of the row (in the higher tile of a pair).Generally, the position in the row (the column) is not needed.

With the exception of TILECONFIG and STTILECFG, successfully executingmatrix (tile) instructions will set both startRow and startP to zero.

Any time an interrupted matrix (tile) instruction is not restarted, itis the responsibility of software to zero the startRow and startPvalues. For example, unmasked floating point exception handlers mightdecide to finish the operation in software and change the programcounter value to another instruction, usually the next instruction. Inthis case the software exception handler must zero the startRow andstartP values in the exception presented to it by the operating systembefore resuming the program. The operating system will subsequentlyreload those values using a restore instruction.

Byte 3 stores an indication of pairs (1b per tile) of tiles 1907.

Bytes 16-17 store the number of rows 1913 and columns 1915 for tile 0,bytes 18-19 store the number of rows and columns for tile 1, etc. Inother words, each 2 byte group specifies a number of rows and columnsfor a tile. If a group of 2 bytes is not used to specify tileparameters, they should have the value zero. Specifying tile parametersfor more tiles than the implementation limit or the palette limitresults in a fault. Unconfigured tiles are set to an initial state with0 rows, 0 columns.

Finally, the configuration in memory typically ends with an endingdelineation such as all zeros for several consecutive bytes.

ii. Exemplary Tile and Tile Configuration Storage

FIGS. 20(A)-(D) illustrate examples of register(s) 1819. FIG. 20(A)illustrates a plurality of registers 1819. As shown each tile (TMM0 2001. . . TMMN 2003) has a separate register with each register storing arow and column size for that particular tile. StartP and StartRow arestored in separate registers 2011 and 2013. One or more status registers2015 are set (e.g., TILES_CONFIGURED=1) to indicate tiles are configuredfor use.

FIG. 20(B) illustrates a plurality of registers 1819. As shown each tilehas separate registers for its rows and columns. For example, TMM0 rowsconfiguration 2021, TMM0 columns configuration 2023, StartP and StartRoware stored in separate registers 2011 and 2013. One or more statusregisters 2015 are set (e.g., TILES_CONFIGURED=1) to indicate tiles areconfigured for use.

FIG. 20(C) illustrates a single register 1819. As shown, this registerstores tile configurations (rows and columns per tile) 2031, StartP2011, and StartRow 2013 are stored in single register as packed dataregisters. One or more status registers 2015 are set (e.g.,TILES_CONFIGURED=1) to indicate tiles are configured for use.

FIG. 20(D) illustrates a plurality of registers 1819. As shown, a singleregister stores tile configurations (rows and columns per tile) 2031.StartP and StartRow are stored in separate registers 2011 and 2013. Oneor more status registers 2015 are set (e.g., TILES_CONFIGURED=1) toindicate tiles are configured for use.

Other combinations are contemplated such as combining the startregisters into a single register where they are shown separately, etc.

I. Exemplary Execution

FIG. 21 illustrates an exemplary execution of a TZPAIR instruction. TheTZPAIR instruction format includes fields for an opcode and adestination tile identifier tmm0 to identify a pair of tiles having Mrows, N columns, and PAIR and VALID parameters both set to TRUE. Asshown, a decoded TZPAIR instruction 2102 is received by executioncircuitry 2104, which, in some embodiments, uses a grid of FMAs 2106 towrite a zero to every element of the left and right destination matrices(tiles) 2108 and 2110. As detailed earlier, the left and rightdestination matrices {tiles} may be stored in a collection of registers,locations in memory, or in other storage accessible to executioncircuitry.

As shown, execution circuity 2104 executes a decoded TZPAIR instruction2102 to zero the elements of the left destination matrix (tile) 2108 andthe right destination matrix (tile) 2110.

Also shown are remaining (unconfigured) columns and rows being set tozero which is done in some embodiments. In some embodiments, a matrix(tile) is configured to use only a subset of the rows and columnspossible. For example, a matrix (tile) may have up to 16 rows andcolumns to use, but only use 4 of each. The configuration of each matrix(tile) is typically done by the execution of a configuration instructionprior to matrix (tile) usage. In this example, there are N columns and Mrows possible.

II. Exemplary Instruction Format(S)

An embodiment of a format for a TZPAIR instruction is TZPAIR{B/W/D/Q}TMM0. In some embodiments, TZPAIR{B/W/D/Q} is the opcode mnemonic of theinstruction where B/W/D/Q represent data element sizes (byte, word,double word, quadword) of the two destinations. In some embodiments, theTMM2 field is a R/M value (such as 2546 of FIGS. 25A-B), the TMM1 fieldis REG 2544 of FIGS. 25A-B, and the data element size is found in 2564of FIGS. 25A-B.

In embodiments, encodings of the instruction include a scale-index-base(SIB) type memory addressing operand that indirectly identifies multipleindexed destination locations in memory (e.g., field 2550 of FIGS.25A-B). In one embodiment, an SIB type memory operand may include anencoding identifying a base address register. The contents of the baseaddress register may represent a base address in memory from which theaddresses of the particular destination locations in memory arecalculated. For example, the base address may be the address of thefirst location in a block of potential destination locations for anextended vector instruction. In one embodiment, an SIB type memoryoperand may include an encoding identifying an index register. Eachelement of the index register may specify an index or offset valueusable to compute, from the base address, an address of a respectivedestination location within a block of potential destination locations.In one embodiment, an SIB type memory operand may include an encodingspecifying a scaling factor to be applied to each index value whencomputing a respective destination address. For example, if a scalingfactor value of four is encoded in the SIB type memory operand, eachindex value obtained from an element of the index register may bemultiplied by four and then added to the base address to compute adestination address.

In one embodiment, an SIB type memory operand of the form vm32{x,y,z}may identify a vector array of memory operands specified using SIB typememory addressing. In this example, the array of memory addresses isspecified using a common base register, a constant scaling factor, and avector index register containing individual elements, each of which is a32-bit index value. The vector index register may be a 128-bit register(e.g., XMM) register (vm32 x), a 256-bit (e.g., YMM) register (vm32 y),or a 512-bit (e.g., ZMM) register (vm32 z). In another embodiment, anSIB type memory operand of the form vm64{x,y,z} may identify a vectorarray of memory operands specified using SIB type memory addressing. Inthis example, the array of memory addresses is specified using a commonbase register, a constant scaling factor, and a vector index registercontaining individual elements, each of which is a 64-bit index value.The vector index register may be a 128-bit register (e.g., XMM) register(vm64 x), a 256-bit (e.g., YMM) register (vm64 y) or a 512-bit (e.g.,ZMM) register (vm64 z).

III. Exemplary Method(s) of Execution

FIG. 22 illustrates an embodiment of method performed by a processor toprocess a TZPAIR instruction.

At 2201, an instruction is fetched. For example, a TZPAIR instruction isfetched having fields for an opcode and a destination matrix (tile)operand having a pair parameter equal to true. In some embodiments, theinstruction is fetched from an instruction cache. The opcode of theTZPAIR instruction indicates a zeroing of packed data element positionsof left and right matrices (tiles) of the identified destination matrix(tile). In some embodiments, the opcode of the TZPAIR instructionincludes a suffix, such as “B,” “W,” “D,” or “Q” to specify a size ofeach of the tile elements as being a byte, a word, a doubleword, and aquadword, respectively.

The fetched instruction is decoded at 2203. For example, the fetchedTZPAIR instruction is decoded by decode circuitry such as that detailedherein.

Execution of the decoded instruction is scheduled (as needed) at 2205.

At 2207, the decoded TZPAIR instruction is executed by executioncircuitry (hardware) such as that detailed herein. For the TZPAIRinstruction, the execution will cause execution circuitry to zero theelements of the left and right matrices (tiles) of the identifieddestination matrix (tile). In some embodiments, unconfigured elements ofrows of the destination matrix (tile) are also zeroed.

In some embodiments, the instruction is committed or retired at 2209.

FIG. 23 illustrates a more detailed description of an execution of aTZPAIR instruction. Typically, this is performed by execution circuitrysuch as that detailed above.

At 2302, a determination of whether ALL of the following is true ismade: 1) is there at least one configured matrix (tile)? 2) does theidentified destination matrix (tile) have a VALID parameter set to TRUE?and 3) does the identified destination matrix (tile) have a PAIRparameter set to TRUE? When any of these is not true, a fault isgenerated at 2304.

When all of the conditions tested at 2302 are true, execution circuitryat 2306 loops over each row M of a left matrix (tile) and a right matrix(tile) of the identified destination matrix (tile), starting with thefirst row. For each row, the execution circuitry executes an inner loopat 2308, looping over each column N of the left matrix (tile) and theright matrix (tile) of the identified destination matrix (tile),starting with the first column. For each of the elements of the innerloop, the execution circuitry determines at 2310 how many bytes arecontained in each element of the destination matrices (tiles). Forexample, the TZPAIR instruction may include an operand, an opcodeprefix, or an opcode suffix being one of a “B,” “W,” “D,” and “Q” tospecify element sizes of 1 byte, 2 bytes, 4 bytes, and 8 bytes,respectively. When the left matrix (tile) elements and right matrix(tile) elements of the identified destination matrix (tile) contain 1byte, the execution circuitry at 2312 sets each byte-sized element tozero. When the left matrix (tile) elements and right matrix (tile)elements of the identified destination matrix (tile) contain 2 bytes,the execution circuitry at 2314 sets each word-sized element to zero.When the left matrix (tile) elements and right matrix (tile) elements ofthe identified destination matrix (tile) contain 4 bytes, the executioncircuitry at 2316 sets each doubleword-sized element to zero. When theleft matrix (tile) elements and right matrix (tile) elements of theidentified destination matrix (tile) contain 8 bytes, the executioncircuitry at 2318 sets each quadword-sized element to zero.

After setting elements of the left matrix (tile) and the right matrix(tile) of the identified destination matrix (tile) at one of 2312, 2314,2316, and 2318, the execution circuitry at 2320 increments N anddetermines whether any columns remain in the inner loop, and, if so,continues to 2308 to perform the next iteration of the inner loop. Butwhen the determination at 2320 indicates that no columns remain, theexecution circuitry at 2322 increments M and determines whether any rowsremain in the outer loop, and, if so, continues to 2306 to perform thenext iteration of the outer loop. But, when the determination at 2322indicates that no rows remain, the process ends.

IV. Exemplary Pseudocode

FIG. 24 is exemplary pseudocode describing an embodiment of a methodperformed by a processor to process a TZPAIR instruction. As shown inpseudocode 2402, the TZPAIR instruction includes an opcode, TZPAIRB, anda destination matrix (tile) identifier to identify a configured matrix(tile) having VALID and PAIR parameters set to TRUE. The suffix, “B,”included in the opcode, indicates that the destination matrix (tile)includes a left matrix (tile), tmm1.left, and a right matrix (tile),tmm1.right, having byte-sized elements. As shown, the pseudocode 2402first causes the execution circuitry to generate a fault if any of threeerror checks fails. Then the pseudocode causes the processor to loopover each row j and each column k of the left and right matrices(tiles), tmm1.left and tmm1.right. At each element, the processor setsthe element at tmm1.left[j][k] and tmm1.right[j][k] to zero.

Pseudocode 2404 operates similarly to pseudocode 2402, but processes aninstruction having an opcode with a “W” suffix, indicating that theelements of the left and right matrices (tiles), tmm1.left andtmm1.right, are each two bytes in size.

Pseudocode 2406 operates similarly to pseudocode 2402, but processes aninstruction having an opcode with a “D” suffix, indicating that theelements of the left and right matrices (tiles), tmm1.left andtmm1.right, are each four bytes in size.

Pseudocode 2408 operates similarly to pseudocode 2402, but processes aninstruction having an opcode with a “Q” suffix, indicating that theelements of the left and right matrices (tiles), tmm1.left andtmm1.right, are each eight bytes in size. The pseudocode 2408 performsthe zeroing in a slightly different order than that of pseudocode 2402,as a first loop zeroes all elements of the left matrix (tile), and asecond loop zeroes all elements of the right matrix (tile).

Further Examples

Example 1 provides a processor including: decode circuitry to decode amatrix pair zeroing instruction having fields for an opcode and anidentifier to identify a destination matrix having a PAIR parameterequal to TRUE, and execution circuitry to execute the decoded matrixpair zeroing instruction to zero every element of a left matrix and aright matrix of the identified destination matrix.

Example 2 includes the substance of the exemplary processor of Example1, wherein the opcode defines a size of each data element of the leftand right matrices.

Example 3 includes the substance of the exemplary processor of Example2, wherein the size of each data element of the left and right matricesis a doubleword.

Example 4 includes the substance of the exemplary processor of Example2, wherein the size of each data element of the left and right matricesis a word.

Example 5 includes the substance of the exemplary processor of any ofExamples 1-4, wherein the execution circuitry is further to zero anydata elements in remaining columns of the left and right matrices andunconfigured rows of the left and right matrices.

Example 6 includes the substance of the exemplary processor of any ofExamples 1-4, wherein the left and right matrices are each a pluralityof registers to represent a matrix.

Example 7 includes the substance of the exemplary processor of any ofExamples 1-4, wherein the execution circuitry is to fault upon adetermination of at least one of: a number of configured tiles equalszero, the PAIR parameter of the identified destination matrix is not setto TRUE, and a VALID parameter of the identified destination matrix isnot set to TRUE.

Example 8 provides a method including: decoding a matrix pair zeroinginstruction having fields for an opcode and a destination matrixidentifier to identify a destination matrix having a PAIR parameterequal to TRUE, and executing the decoded matrix pair zeroing instructionto zero every element of a left matrix and a right matrix of theidentified destination matrix.

Example 9 includes the substance of the exemplary method of Example 8,wherein the opcode defines a size of each data element of the left andright matrices.

Example 10 includes the substance of the exemplary method of Example 9,wherein the size of each data element of the left and right matrices isa doubleword.

Example 11 includes the substance of the exemplary method of Example 9,wherein the size of each data element of the left and right matrices isa word.

Example 12 includes the substance of the exemplary method of any ofExamples 8-11, further including zeroing any data elements in remainingcolumns of the left and right matrices and unconfigured rows of the leftand right matrices.

Example 13 includes the substance of the exemplary method of any ofExamples 8-11, wherein the left and right matrices are each a pluralityof registers to represent a matrix.

Example 14 includes the substance of the exemplary method of any ofExamples 8-11, further including: faulting upon a determination of atleast one of: a number of configured tiles equals zero, the PAIRparameter of the identified destination matrix is not set to TRUE, and aVALID parameter of the identified destination matrix is not set to TRUE.

Example 15 provides a non-transitory machine-readable medium storing amatrix pair zeroing instruction which causes a processor to execute theinstruction by: decoding the matrix pair zeroing instruction havingfields for an opcode and a destination matrix identifier to identify adestination matrix having a PAIR parameter equal to TRUE, and executingthe decoded matrix pair zeroing instruction to zero every element of aleft matrix and a right matrix of the identified destination matrix.

Example 16 includes the substance of the exemplary non-transitorymachine-readable medium of Example 15, wherein the opcode defines a sizeof each data element of the left and right matrices.

Example 17 includes the substance of the exemplary non-transitorymachine-readable medium of Example 15, wherein the size of each dataelement of the left and right matrices is a doubleword.

Example 18 includes the substance of the exemplary non-transitorymachine-readable medium of Example 15, wherein the size of each dataelement of the left and right matrices is a word.

Example 19 includes the substance of the exemplary non-transitorymachine-readable medium of any of Examples 15-18, further includingzeroing any data elements in remaining columns of the left and rightmatrices and unconfigured rows of the left and right matrices.

Example 20 includes the substance of the exemplary non-transitorymachine-readable medium of any of Examples 15-18, wherein the left andright matrices are each a plurality of registers to represent a matrix.

Example 21 includes the substance of the exemplary non-transitorymachine-readable medium of any of Examples 15-18, further including:faulting upon a determination of at least one of: a number of configuredtiles equals zero, the PAIR parameter of the identified destinationmatrix is not set to TRUE, and a VALID parameter of the identifieddestination matrix is not set to TRUE.

Example 22 provides a system including: a processor, and an acceleratorcoupled to the processor, the accelerator including: decode circuitry todecode a matrix pair zeroing instruction having fields for an opcode anda destination matrix identifier to identify a destination matrix havinga PAIR parameter equal to TRUE, and execution circuitry to execute thedecoded matrix pair zeroing instruction to zero every element of a leftmatrix and a right matrix of the identified destination matrix.

Example 23 includes the substance of the exemplary system of Example 22,wherein the opcode defines a size of each data element of the left andright matrices.

Example 24 includes the substance of the exemplary system of any ofExamples 22-23, wherein the execution circuitry is further to zero anydata elements in remaining columns of the left and right matrices andunconfigured rows of the left and right matrices.

Example 25 includes the substance of the exemplary system of any ofExamples 22-23, wherein the left and right matrices are each a pluralityof registers to represent a matrix.

V. Detailed Exemplary Systems, Processors, and Emulation

Detailed herein are examples of hardware, software, etc. to execute theabove described instructions. For example, what is described belowdetails aspects of instruction execution including various pipelinestages such as fetch, decode, schedule, execute, retire, etc.

Instruction Sets

An instruction set may include one or more instruction formats. A giveninstruction format may define various fields (e.g., number of bits,location of bits) to specify, among other things, the operation to beperformed (e.g., opcode) and the operand(s) on which that operation isto be performed and/or other data field(s) (e.g., mask). Someinstruction formats are further broken down though the definition ofinstruction templates (or subformats). For example, the instructiontemplates of a given instruction format may be defined to have differentsubsets of the instruction format's fields (the included fields aretypically in the same order, but at least some have different bitpositions because there are less fields included) and/or defined to havea given field interpreted differently. Thus, each instruction of an ISAis expressed using a given instruction format (and, if defined, in agiven one of the instruction templates of that instruction format) andincludes fields for specifying the operation and the operands. Forexample, an exemplary ADD instruction has a specific opcode and aninstruction format that includes an opcode field to specify that opcodeand operand fields to select operands (source1/destination and source2);and an occurrence of this ADD instruction in an instruction stream willhave specific contents in the operand fields that select specificoperands. A set of SIMD extensions referred to as the Advanced VectorExtensions (AVX) (AVX1 and AVX2) and using the Vector Extensions (VEX)coding scheme has been released and/or published (e.g., see Intel® 64and IA-32 Architectures Software Developer's Manual, September 2014; andsee Intel® Advanced Vector Extensions Programming Reference, October2014).

Exemplary Instruction Formats

Embodiments of the instruction(s) described herein may be embodied indifferent formats. Additionally, exemplary systems, architectures, andpipelines are detailed below. Embodiments of the instruction(s) may beexecuted on such systems, architectures, and pipelines, but are notlimited to those detailed.

Generic Vector Friendly Instruction Format

A vector friendly instruction format is an instruction format that issuited for vector instructions (e.g., there are certain fields specificto vector operations). While embodiments are described in which bothvector and scalar operations are supported through the vector friendlyinstruction format, alternative embodiments use only vector operationsthe vector friendly instruction format.

FIGS. 25A-25B are block diagrams illustrating a generic vector friendlyinstruction format and instruction templates thereof according toembodiments of the invention. FIG. 25A is a block diagram illustrating ageneric vector friendly instruction format and class A instructiontemplates thereof according to embodiments of the invention; while FIG.25B is a block diagram illustrating the generic vector friendlyinstruction format and class B instruction templates thereof accordingto embodiments of the invention. Specifically, a generic vector friendlyinstruction format 2500 for which are defined class A and class Binstruction templates, both of which include no memory access 2505instruction templates and memory access 2520 instruction templates. Theterm generic in the context of the vector friendly instruction formatrefers to the instruction format not being tied to any specificinstruction set.

While embodiments of the invention will be described in which the vectorfriendly instruction format supports the following: a 64 byte vectoroperand length (or size) with 32 bit (4 byte) or 64 bit (8 byte) dataelement widths (or sizes) (and thus, a 64 byte vector consists of either16 doubleword-size elements or alternatively, 8 quadword-size elements);a 64 byte vector operand length (or size) with 16 bit (2 byte) or 8 bit(1 byte) data element widths (or sizes); a 32 byte vector operand length(or size) with 32 bit (4 byte), 64 bit (8 byte), 16 bit (2 byte), or 8bit (1 byte) data element widths (or sizes); and a 16 byte vectoroperand length (or size) with 32 bit (4 byte), 64 bit (8 byte), 16 bit(2 byte), or 8 bit (1 byte) data element widths (or sizes); alternativeembodiments may support more, less and/or different vector operand sizes(e.g., 256 byte vector operands) with more, less, or different dataelement widths (e.g., 128 bit (16 byte) data element widths).

The class A instruction templates in FIG. 25A include: 1) within the nomemory access 2505 instruction templates there is shown a no memoryaccess, full round control type operation 2510 instruction template anda no memory access, data transform type operation 2515 instructiontemplate; and 2) within the memory access 2520 instruction templatesthere is shown a memory access, temporal 2525 instruction template and amemory access, non-temporal 2530 instruction template. The class Binstruction templates in FIG. 25B include: 1) within the no memoryaccess 2505 instruction templates there is shown a no memory access,write mask control, partial round control type operation 2512instruction template and a no memory access, write mask control, vsizetype operation 2517 instruction template; and 2) within the memoryaccess 2520 instruction templates there is shown a memory access, writemask control 2527 instruction template.

The generic vector friendly instruction format 2500 includes thefollowing fields listed below in the order illustrated in FIGS. 25A-25B.

Format field 2540—a specific value (an instruction format identifiervalue) in this field uniquely identifies the vector friendly instructionformat, and thus occurrences of instructions in the vector friendlyinstruction format in instruction streams. As such, this field isoptional in the sense that it is not needed for an instruction set thathas only the generic vector friendly instruction format.

Base operation field 2542—its content distinguishes different baseoperations.

Register index field 2544—its content, directly or through addressgeneration, specifies the locations of the source and destinationoperands, be they in registers or in memory. These include a sufficientnumber of bits to select N registers from a P×Q (e.g. 32×512, 16×128,32×1024, 64×1024) register file. While in one embodiment N may be up tothree sources and one destination register, alternative embodiments maysupport more or less sources and destination registers (e.g., maysupport up to two sources where one of these sources also acts as thedestination, may support up to three sources where one of these sourcesalso acts as the destination, may support up to two sources and onedestination).

Modifier field 2546—its content distinguishes occurrences ofinstructions in the generic vector instruction format that specifymemory access from those that do not; that is, between no memory access2505 instruction templates and memory access 2520 instruction templates.Memory access operations read and/or write to the memory hierarchy (insome cases specifying the source and/or destination addresses usingvalues in registers), while non-memory access operations do not (e.g.,the source and destinations are registers). While in one embodiment thisfield also selects between three different ways to perform memoryaddress calculations, alternative embodiments may support more, less, ordifferent ways to perform memory address calculations.

Augmentation operation field 2550—its content distinguishes which one ofa variety of different operations to be performed in addition to thebase operation. This field is context specific. In one embodiment of theinvention, this field is divided into a class field 2568, an alpha field2552, and a beta field 2554. The augmentation operation field 2550allows common groups of operations to be performed in a singleinstruction rather than 2, 3, or 4 instructions.

Scale field 2560—its content allows for the scaling of the index field'scontent for memory address generation (e.g., for address generation thatuses 2^(scale)*index+base).

Displacement Field 2562A—its content is used as part of memory addressgeneration (e.g., for address generation that uses2^(scale)*index+base+displacement).

Displacement Factor Field 2562B (note that the juxtaposition ofdisplacement field 2562A directly over displacement factor field 2562Bindicates one or the other is used)—its content is used as part ofaddress generation; it specifies a displacement factor that is to bescaled by the size of a memory access (N)—where N is the number of bytesin the memory access (e.g., for address generation that uses2^(scale)*index+base+scaled displacement). Redundant low-order bits areignored and hence, the displacement factor field's content is multipliedby the memory operands total size (N) in order to generate the finaldisplacement to be used in calculating an effective address. The valueof N is determined by the processor hardware at runtime based on thefull opcode field 2574 (described later herein) and the datamanipulation field 2554C. The displacement field 2562A and thedisplacement factor field 2562B are optional in the sense that they arenot used for the no memory access 2505 instruction templates and/ordifferent embodiments may implement only one or none of the two.

Data element width field 2564—its content distinguishes which one of anumber of data element widths is to be used (in some embodiments for allinstructions; in other embodiments for only some of the instructions).This field is optional in the sense that it is not needed if only onedata element width is supported and/or data element widths are supportedusing some aspect of the opcodes.

Write mask field 2570—its content controls, on a per data elementposition basis, whether that data element position in the destinationvector operand reflects the result of the base operation andaugmentation operation. Class A instruction templates supportmerging-writemasking, while class B instruction templates support bothmerging- and zeroing-writemasking. When merging, vector masks allow anyset of elements in the destination to be protected from updates duringthe execution of any operation (specified by the base operation and theaugmentation operation); in other one embodiment, preserving the oldvalue of each element of the destination where the corresponding maskbit has a 0. In contrast, when zeroing vector masks allow any set ofelements in the destination to be zeroed during the execution of anyoperation (specified by the base operation and the augmentationoperation); in one embodiment, an element of the destination is set to 0when the corresponding mask bit has a 0 value. A subset of thisfunctionality is the ability to control the vector length of theoperation being performed (that is, the span of elements being modified,from the first to the last one); however, it is not necessary that theelements that are modified be consecutive. Thus, the write mask field2570 allows for partial vector operations, including loads, stores,arithmetic, logical, etc. While embodiments of the invention aredescribed in which the write mask field's 2570 content selects one of anumber of write mask registers that contains the write mask to be used(and thus the write mask field's 2570 content indirectly identifies thatmasking to be performed), alternative embodiments instead or additionalallow the mask write field's 2570 content to directly specify themasking to be performed.

Immediate field 2572—its content allows for the specification of animmediate. This field is optional in the sense that is it not present inan implementation of the generic vector friendly format that does notsupport immediate and it is not present in instructions that do not usean immediate.

Class field 2568—its content distinguishes between different classes ofinstructions. With reference to FIGS. 25A-B, the contents of this fieldselect between class A and class B instructions. In FIGS. 25A-B, roundedcorner squares are used to indicate a specific value is present in afield (e.g., class A 2568A and class B 2568B for the class field 2568respectively in FIGS. 25A-B).

Instruction Templates of Class A

In the case of the non-memory access 2505 instruction templates of classA, the alpha field 2552 is interpreted as an RS field 2552A, whosecontent distinguishes which one of the different augmentation operationtypes are to be performed (e.g., round 2552A.1 and data transform2552A.2 are respectively specified for the no memory access, round typeoperation 2510 and the no memory access, data transform type operation2515 instruction templates), while the beta field 2554 distinguisheswhich of the operations of the specified type is to be performed. In theno memory access 2505 instruction templates, the scale field 2560, thedisplacement field 2562A, and the displacement scale field 2562B are notpresent.

No-Memory Access Instruction Templates—Full Round Control Type Operation

In the no memory access full round control type operation 2510instruction template, the beta field 2554 is interpreted as a roundcontrol field 2554A, whose content(s) provide static rounding. While inthe described embodiments of the invention the round control field 2554Aincludes a suppress all floating point exceptions (SAE) field 2556 and around operation control field 2558, alternative embodiments may supportmay encode both these concepts into the same field or only have one orthe other of these concepts/fields (e.g., may have only the roundoperation control field 2558).

SAE field 2556—its content distinguishes whether or not to disable theexception event reporting; when the SAE field's 2556 content indicatessuppression is enabled, a given instruction does not report any kind offloating-point exception flag and does not raise any floating pointexception handler.

Round operation control field 2558—its content distinguishes which oneof a group of rounding operations to perform (e.g., Round-up,Round-down, Round-towards-zero and Round-to-nearest). Thus, the roundoperation control field 2558 allows for the changing of the roundingmode on a per instruction basis. In one embodiment of the inventionwhere a processor includes a control register for specifying roundingmodes, the round operation control field's 2550 content overrides thatregister value.

No Memory Access Instruction Templates—Data Transform Type Operation

In the no memory access data transform type operation 2515 instructiontemplate, the beta field 2554 is interpreted as a data transform field25546, whose content distinguishes which one of a number of datatransforms is to be performed (e.g., no data transform, swizzle,broadcast).

In the case of a memory access 2520 instruction template of class A, thealpha field 2552 is interpreted as an eviction hint field 2552B, whosecontent distinguishes which one of the eviction hints is to be used (inFIG. 25A, temporal 2552B.1 and non-temporal 2552B.2 are respectivelyspecified for the memory access, temporal 2525 instruction template andthe memory access, non-temporal 2530 instruction template), while thebeta field 2554 is interpreted as a data manipulation field 2554C, whosecontent distinguishes which one of a number of data manipulationoperations (also known as primitives) is to be performed (e.g., nomanipulation; broadcast; up conversion of a source; and down conversionof a destination). The memory access 2520 instruction templates includethe scale field 2560, and optionally the displacement field 2562A or thedisplacement scale field 2562B.

Vector memory instructions perform vector loads from and vector storesto memory, with conversion support. As with regular vector instructions,vector memory instructions transfer data from/to memory in a dataelement-wise fashion, with the elements that are actually transferred isdictated by the contents of the vector mask that is selected as thewrite mask.

Memory Access Instruction Templates—Temporal

Temporal data is data likely to be reused soon enough to benefit fromcaching. This is, however, a hint, and different processors mayimplement it in different ways, including ignoring the hint entirely.

Memory Access Instruction Templates—Non-Temporal

Non-temporal data is data unlikely to be reused soon enough to benefitfrom caching in the 1st-level cache and should be given priority foreviction. This is, however, a hint, and different processors mayimplement it in different ways, including ignoring the hint entirely.

Instruction Templates of Class B

In the case of the instruction templates of class B, the alpha field2552 is interpreted as a write mask control (Z) field 2552C, whosecontent distinguishes whether the write masking controlled by the writemask field 2570 should be a merging or a zeroing.

In the case of the non-memory access 2505 instruction templates of classB, part of the beta field 2554 is interpreted as an RL field 2557A,whose content distinguishes which one of the different augmentationoperation types are to be performed (e.g., round 2557A.1 and vectorlength (VSIZE) 2557A.2 are respectively specified for the no memoryaccess, write mask control, partial round control type operation 2512instruction template and the no memory access, write mask control, VSIZEtype operation 2517 instruction template), while the rest of the betafield 2554 distinguishes which of the operations of the specified typeis to be performed. In the no memory access 2505 instruction templates,the scale field 2560, the displacement field 2562A, and the displacementscale filed 2562B are not present.

In the no memory access, write mask control, partial round control typeoperation 2510 instruction template, the rest of the beta field 2554 isinterpreted as a round operation field 2559A and exception eventreporting is disabled (a given instruction does not report any kind offloating-point exception flag and does not raise any floating pointexception handler).

Round operation control field 2559A—just as round operation controlfield 2558, its content distinguishes which one of a group of roundingoperations to perform (e.g., Round-up, Round-down, Round-towards-zeroand Round-to-nearest). Thus, the round operation control field 2559Aallows for the changing of the rounding mode on a per instruction basis.In one embodiment of the invention where a processor includes a controlregister for specifying rounding modes, the round operation controlfield's 2550 content overrides that register value.

In the no memory access, write mask control, VSIZE type operation 2517instruction template, the rest of the beta field 2554 is interpreted asa vector length field 2559B, whose content distinguishes which one of anumber of data vector lengths is to be performed on (e.g., 128, 256, or512 byte).

In the case of a memory access 2520 instruction template of class B,part of the beta field 2554 is interpreted as a broadcast field 2557B,whose content distinguishes whether or not the broadcast type datamanipulation operation is to be performed, while the rest of the betafield 2554 is interpreted the vector length field 2559B. The memoryaccess 2520 instruction templates include the scale field 2560, andoptionally the displacement field 2562A or the displacement scale field2562B.

With regard to the generic vector friendly instruction format 2500, afull opcode field 2574 is shown including the format field 2540, thebase operation field 2542, and the data element width field 2564. Whileone embodiment is shown where the full opcode field 2574 includes all ofthese fields, the full opcode field 2574 includes less than all of thesefields in embodiments that do not support all of them. The full opcodefield 2574 provides the operation code (opcode).

The augmentation operation field 2550, the data element width field2564, and the write mask field 2570 allow these features to be specifiedon a per instruction basis in the generic vector friendly instructionformat.

The combination of write mask field and data element width field createtyped instructions in that they allow the mask to be applied based ondifferent data element widths.

The various instruction templates found within class A and class B arebeneficial in different situations. In some embodiments of theinvention, different processors or different cores within a processormay support only class A, only class B, or both classes. For instance, ahigh performance general purpose out-of-order core intended forgeneral-purpose computing may support only class B, a core intendedprimarily for graphics and/or scientific (throughput) computing maysupport only class A, and a core intended for both may support both (ofcourse, a core that has some mix of templates and instructions from bothclasses but not all templates and instructions from both classes iswithin the purview of the invention). Also, a single processor mayinclude multiple cores, all of which support the same class or in whichdifferent cores support different class. For instance, in a processorwith separate graphics and general purpose cores, one of the graphicscores intended primarily for graphics and/or scientific computing maysupport only class A, while one or more of the general purpose cores maybe high performance general purpose cores with out of order executionand register renaming intended for general-purpose computing thatsupport only class B. Another processor that does not have a separategraphics core, may include one more general purpose in-order orout-of-order cores that support both class A and class B. Of course,features from one class may also be implement in the other class indifferent embodiments of the invention. Programs written in a high levellanguage would be put (e.g., just in time compiled or staticallycompiled) into an variety of different executable forms, including: 1) aform having only instructions of the class(es) supported by the targetprocessor for execution; or 2) a form having alternative routineswritten using different combinations of the instructions of all classesand having control flow code that selects the routines to execute basedon the instructions supported by the processor which is currentlyexecuting the code.

Exemplary Specific Vector Friendly Instruction Format

FIG. 26A is a block diagram illustrating an exemplary specific vectorfriendly instruction format according to embodiments of the invention.FIG. 26A shows a specific vector friendly instruction format 2600 thatis specific in the sense that it specifies the location, size,interpretation, and order of the fields, as well as values for some ofthose fields. The specific vector friendly instruction format 2600 maybe used to extend the x86 instruction set, and thus some of the fieldsare similar or the same as those used in the existing x86 instructionset and extension thereof (e.g., AVX). This format remains consistentwith the prefix encoding field, real opcode byte field, MOD R/M field,SIB field, displacement field, and immediate fields of the existing x86instruction set with extensions. The fields from FIG. 25 into which thefields from FIG. 26A map are illustrated.

It should be understood that, although embodiments of the invention aredescribed with reference to the specific vector friendly instructionformat 2600 in the context of the generic vector friendly instructionformat 2500 for illustrative purposes, the invention is not limited tothe specific vector friendly instruction format 2600 except whereclaimed. For example, the generic vector friendly instruction format2500 contemplates a variety of possible sizes for the various fields,while the specific vector friendly instruction format 2600 is shown ashaving fields of specific sizes. By way of specific example, while thedata element width field 2564 is illustrated as a one bit field in thespecific vector friendly instruction format 2600, the invention is notso limited (that is, the generic vector friendly instruction format 2500contemplates other sizes of the data element width field 2564).

The generic vector friendly instruction format 2500 includes thefollowing fields listed below in the order illustrated in FIG. 26A.

EVEX Prefix (Bytes 0-3) 2602—is encoded in a four-byte form.

Format Field 2540 (EVEX Byte 0, bits [7:0])—the first byte (EVEX Byte 0)is the format field 2540 and it contains 0x62 (the unique value used fordistinguishing the vector friendly instruction format in one embodimentof the invention).

The second-fourth bytes (EVEX Bytes 1-3) include a number of bit fieldsproviding specific capability.

REX field 2605 (EVEX Byte 1, bits [7-5])—consists of a EVEX.R bit field(EVEX Byte 1, bit [7]-R), EVEX.X bit field (EVEX byte 1, bit [6]-X), and2557BEX byte 1, bit[5]-B). The EVEX.R, EVEX.X, and EVEX.B bit fieldsprovide the same functionality as the corresponding VEX bit fields, andare encoded using 1s complement form, i.e. ZMM0 is encoded as 1111B,ZMM15 is encoded as 0000B. Other fields of the instructions encode thelower three bits of the register indexes as is known in the art (rrr,xxx, and bbb), so that Rrrr, Xxxx, and Bbbb may be formed by addingEVEX.R, EVEX.X, and EVEX.B.

REX′ field 2510—this is the first part of the REX′ field 2510 and is theEVEX.R′ bit field (EVEX Byte 1, bit [4]-R′) that is used to encodeeither the upper 16 or lower 16 of the extended 32 register set. In oneembodiment of the invention, this bit, along with others as indicatedbelow, is stored in bit inverted format to distinguish (in thewell-known x86 32-bit mode) from the BOUND instruction, whose realopcode byte is 62, but does not accept in the MOD R/M field (describedbelow) the value of 11 in the MOD field; alternative embodiments of theinvention do not store this and the other indicated bits below in theinverted format. A value of 1 is used to encode the lower 16 registers.In other words, R′Rrrr is formed by combining EVEX.R′, EVEX.R, and theother RRR from other fields.

Opcode map field 2615 (EVEX byte 1, bits [3:0]-mmmm)—its content encodesan implied leading opcode byte (0F, 0F 38, or 0F 3).

Data element width field 2564 (EVEX byte 2, bit [7]-W)—is represented bythe notation EVEX.W. EVEX.W is used to define the granularity (size) ofthe datatype (either 32-bit data elements or 64-bit data elements).

EVEX.vvvv 2620 (EVEX Byte 2, bits [6:3]-vvvv)—the role of EVEX.vvvv mayinclude the following: 1) EVEX.vvvv encodes the first source registeroperand, specified in inverted (1s complement) form and is valid forinstructions with 2 or more source operands; 2) EVEX.vvvv encodes thedestination register operand, specified in 1s complement form forcertain vector shifts; or 3) EVEX.vvvv does not encode any operand, thefield is reserved and should contain 1111b. Thus, EVEX.vvvv field 2620encodes the 4 low-order bits of the first source register specifierstored in inverted (1s complement) form. Depending on the instruction,an extra different EVEX bit field is used to extend the specifier sizeto 32 registers.

EVEX.U 2568 Class field (EVEX byte 2, bit [2]-U)—If EVEX.U=0, itindicates class A or EVEX.U0; if EVEX.U=1, it indicates class B orEVEX.U1.

Prefix encoding field 2625 (EVEX byte 2, bits [1:0]-pp)—providesadditional bits for the base operation field. In addition to providingsupport for the legacy SSE instructions in the EVEX prefix format, thisalso has the benefit of compacting the SIMD prefix (rather thanrequiring a byte to express the SIMD prefix, the EVEX prefix requiresonly 2 bits). In one embodiment, to support legacy SSE instructions thatuse a SIMD prefix (66H, F2H, F3H) in both the legacy format and in theEVEX prefix format, these legacy SIMD prefixes are encoded into the SIMDprefix encoding field; and at runtime are expanded into the legacy SIMDprefix prior to being provided to the decoder's PLA (so the PLA canexecute both the legacy and EVEX format of these legacy instructionswithout modification). Although newer instructions could use the EVEXprefix encoding field's content directly as an opcode extension, certainembodiments expand in a similar fashion for consistency but allow fordifferent meanings to be specified by these legacy SIMD prefixes. Analternative embodiment may redesign the PLA to support the 2 bit SIMDprefix encodings, and thus not require the expansion.

Alpha field 2552 (EVEX byte 3, bit [7]-EH; also known as EVEX.EH,EVEX.rs, EVEX.RL, EVEX.write mask control, and EVEX.N; also illustratedwith α)—as previously described, this field is context specific.

Beta field 2554 (EVEX byte 3, bits [6:4]-SSS, also known as EVEX.s₂₋₀,EVEX.r₂₋₀, EVEX.rr1, EVEX.LL0, EVEX.LLB; also illustrated with βββ)—aspreviously described, this field is context specific.

REX′ field 2510—this is the remainder of the REX′ field and is theEVEX.V′ bit field (EVEX Byte 3, bit [3]-V′) that may be used to encodeeither the upper 16 or lower 16 of the extended 32 register set. Thisbit is stored in bit inverted format. A value of 1 is used to encode thelower 16 registers. In other words, V′VVVV is formed by combiningEVEX.V′, EVEX.vvvv.

Write mask field 2570 (EVEX byte 3, bits [2:0]-kkk)—its contentspecifies the index of a register in the write mask registers aspreviously described. In one embodiment of the invention, the specificvalue EVEX.kkk=000 has a special behavior implying no write mask is usedfor the particular instruction (this may be implemented in a variety ofways including the use of a write mask hardwired to all ones or hardwarethat bypasses the masking hardware).

Real Opcode Field 2630 (Byte 4) is also known as the opcode byte. Partof the opcode is specified in this field.

MOD R/M Field 2640 (Byte 5) includes MOD field 2642, Reg field 2644, andR/M field 2646. As previously described, the MOD field's 2642 contentdistinguishes between memory access and non-memory access operations.The role of Reg field 2644 can be summarized to two situations: encodingeither the destination register operand or a source register operand, orbe treated as an opcode extension and not used to encode any instructionoperand. The role of R/M field 2646 may include the following: encodingthe instruction operand that references a memory address, or encodingeither the destination register operand or a source register operand.

Scale, Index, Base (SIB) Byte (Byte 6)—As previously described, thescale field's 2550 content is used for memory address generation.SIB.xxx 2654 and SIB.bbb 2656—the contents of these fields have beenpreviously referred to with regard to the register indexes Xxxx andBbbb.

Displacement field 2562A (Bytes 7-10)—when MOD field 2642 contains 10,bytes 7-10 are the displacement field 2562A, and it works the same asthe legacy 32-bit displacement (disp32) and works at byte granularity.

Displacement factor field 2562B (Byte 7)—when MOD field 2642 contains01, byte 7 is the displacement factor field 2562B. The location of thisfield is that same as that of the legacy x86 instruction set 8-bitdisplacement (disp8), which works at byte granularity. Since disp8 issign extended, it can only address between −128 and 127 bytes offsets;in terms of 64 byte cache lines, disp8 uses 8 bits that can be set toonly four really useful values −128, −64, 0, and 64; since a greaterrange is often needed, disp32 is used; however, disp32 requires 4 bytes.In contrast to disp8 and disp32, the displacement factor field 2562B isa reinterpretation of disp8; when using displacement factor field 2562B,the actual displacement is determined by the content of the displacementfactor field multiplied by the size of the memory operand access (N).This type of displacement is referred to as disp8*N. This reduces theaverage instruction length (a single byte of used for the displacementbut with a much greater range). Such compressed displacement is based onthe assumption that the effective displacement is multiple of thegranularity of the memory access, and hence, the redundant low-orderbits of the address offset do not need to be encoded. In other words,the displacement factor field 2562B substitutes the legacy x86instruction set 8-bit displacement. Thus, the displacement factor field2562B is encoded the same way as an x86 instruction set 8-bitdisplacement (so no changes in the ModRM/SIB encoding rules) with theonly exception that disp8 is overloaded to disp8*N. In other words,there are no changes in the encoding rules or encoding lengths but onlyin the interpretation of the displacement value by hardware (which needsto scale the displacement by the size of the memory operand to obtain abyte-wise address offset). Immediate field 2572 operates as previouslydescribed.

Full Opcode Field

FIG. 26B is a block diagram illustrating the fields of the specificvector friendly instruction format 2600 that make up the full opcodefield 2574 according to one embodiment of the invention. Specifically,the full opcode field 2574 includes the format field 2540, the baseoperation field 2542, and the data element width (W) field 2564. Thebase operation field 2542 includes the prefix encoding field 2625, theopcode map field 2615, and the real opcode field 2630.

Register Index Field

FIG. 26C is a block diagram illustrating the fields of the specificvector friendly instruction format 2600 that make up the register indexfield 2544 according to one embodiment of the invention. Specifically,the register index field 2544 includes the REX field 2605, the REX′field 2610, the MODR/M.reg field 2644, the MODR/M.r/m field 2646, theVVVV field 2620, xxx field 2654, and the bbb field 2656.

Augmentation Operation Field

FIG. 26D is a block diagram illustrating the fields of the specificvector friendly instruction format 2600 that make up the augmentationoperation field 2550 according to one embodiment of the invention. Whenthe class (U) field 2568 contains 0, it signifies EVEX.U0 (class A2568A); when it contains 1, it signifies EVEX.U1 (class B 2568B). WhenU=0 and the MOD field 2642 contains 11 (signifying a no memory accessoperation), the alpha field 2552 (EVEX byte 3, bit [7]-EH) isinterpreted as the rs field 2552A. When the rs field 2552A contains a 1(round 2552A.1), the beta field 2554 (EVEX byte 3, bits [6:4]-SSS) isinterpreted as the round control field 2554A. The round control field2554A includes a one bit SAE field 2556 and a two bit round operationfield 2558. When the rs field 2552A contains a 0 (data transform2552A.2), the beta field 2554 (EVEX byte 3, bits [6:4]-SSS) isinterpreted as a three bit data transform field 2554B. When U=0 and theMOD field 2642 contains 00, 01, or 10 (signifying a memory accessoperation), the alpha field 2552 (EVEX byte 3, bit [7]-EH) isinterpreted as the eviction hint (EH) field 2552B and the beta field2554 (EVEX byte 3, bits [6:4]-SSS) is interpreted as a three bit datamanipulation field 2554C.

When U=1, the alpha field 2552 (EVEX byte 3, bit [7]-EH) is interpretedas the write mask control (Z) field 2552C. When U=1 and the MOD field2642 contains 11 (signifying a no memory access operation), part of thebeta field 2554 (EVEX byte 3, bit [4]-S₀) is interpreted as the RL field2557A; when it contains a 1 (round 2557A.1) the rest of the beta field2554 (EVEX byte 3, bit [6-5]-S₂₋₁) is interpreted as the round operationfield 2559A, while when the RL field 2557A contains a 0 (VSIZE 2557.A2)the rest of the beta field 2554 (EVEX byte 3, bit [6-5]-S₂₋₁) isinterpreted as the vector length field 2559B (EVEX byte 3, bit[6-5]-L₁₋₀). When U=1 and the MOD field 2642 contains 00, 01, or 10(signifying a memory access operation), the beta field 2554 (EVEX byte3, bits [6:4]-SSS) is interpreted as the vector length field 2559B (EVEXbyte 3, bit [6-5]-L₁₋₀) and the broadcast field 2557B (EVEX byte 3, bit[4]-B).

Exemplary Register Architecture

FIG. 27 is a block diagram of a register architecture 2700 according toone embodiment of the invention. In the embodiment illustrated, thereare 32 vector registers 2710 that are 512 bits wide; these registers arereferenced as zmm0 through zmm31. The lower order 256 bits of the lower16 zmm registers are overlaid on registers ymm0-16. The lower order 128bits of the lower 16 zmm registers (the lower order 128 bits of the ymmregisters) are overlaid on registers xmm0-15. The specific vectorfriendly instruction format 2600 operates on these overlaid registerfile as illustrated in the below tables.

Adjustable Vector Length Class Operations Registers InstructionTemplates that A (FIG. 2510, 2515, zmm registers (the vector length is64 do not include the vector 25A; U = 0) 2525, 2530 byte) length field2559B B (FIG. 2512 zmm registers (the vector length is 64 25B; U = 1)byte) Instruction templates that B (FIG. 2517, 2527 zmm, ymm, or xmmregisters (the do include the vector 25B; U = 1) vector length is 64byte, 32 byte, or 16 length field 2559B byte) depending on the vectorlength field 2559B

In other words, the vector length field 2559B selects between a maximumlength and one or more other shorter lengths, where each such shorterlength is half the length of the preceding length; and instructionstemplates without the vector length field 2559B operate on the maximumvector length. Further, in one embodiment, the class B instructiontemplates of the specific vector friendly instruction format 2600operate on packed or scalar single/double-precision floating point dataand packed or scalar integer data. Scalar operations are operationsperformed on the lowest order data element position in an zmm/ymm/xmmregister; the higher order data element positions are either left thesame as they were prior to the instruction or zeroed depending on theembodiment.

Write mask registers 2715—in the embodiment illustrated, there are 8write mask registers (k0 through k7), each 64 bits in size. In analternate embodiment, the write mask registers 2715 are 16 bits in size.As previously described, in one embodiment of the invention, the vectormask register k0 cannot be used as a write mask; when the encoding thatwould normally indicate k0 is used for a write mask, it selects ahardwired write mask of 0xFFFF, effectively disabling write masking forthat instruction.

General-purpose registers 2725—in the embodiment illustrated, there aresixteen 64-bit general-purpose registers that are used along with theexisting x86 addressing modes to address memory operands. Theseregisters are referenced by the names RAX, RBX, RCX, RDX, RBP, RSI, RDI,RSP, and R8 through R15.

Scalar floating point stack register file (x87 stack) 2745, on which isaliased the MMX packed integer flat register file 2750—in the embodimentillustrated, the x87 stack is an eight-element stack used to performscalar floating-point operations on 32/64/80-bit floating point datausing the x87 instruction set extension; while the MMX registers areused to perform operations on 64-bit packed integer data, as well as tohold operands for some operations performed between the MMX and XMMregisters.

Alternative embodiments of the invention may use wider or narrowerregisters. Additionally, alternative embodiments of the invention mayuse more, less, or different register files and registers.

Exemplary Core Architectures, Processors, and Computer Architectures

Processor cores may be implemented in different ways, for differentpurposes, and in different processors. For instance, implementations ofsuch cores may include: 1) a general purpose in-order core intended forgeneral-purpose computing; 2) a high performance general purposeout-of-order core intended for general-purpose computing; 3) a specialpurpose core intended primarily for graphics and/or scientific(throughput) computing. Implementations of different processors mayinclude: 1) a CPU including one or more general purpose in-order coresintended for general-purpose computing and/or one or more generalpurpose out-of-order cores intended for general-purpose computing; and2) a coprocessor including one or more special purpose cores intendedprimarily for graphics and/or scientific (throughput). Such differentprocessors lead to different computer system architectures, which mayinclude: 1) the coprocessor on a separate chip from the CPU; 2) thecoprocessor on a separate die in the same package as a CPU; 3) thecoprocessor on the same die as a CPU (in which case, such a coprocessoris sometimes referred to as special purpose logic, such as integratedgraphics and/or scientific (throughput) logic, or as special purposecores); and 4) a system on a chip that may include on the same die thedescribed CPU (sometimes referred to as the application core(s) orapplication processor(s)), the above described coprocessor, andadditional functionality. Exemplary core architectures are describednext, followed by descriptions of exemplary processors and computerarchitectures.

Exemplary Core Architectures

In-Order and Out-of-Order Core Block Diagram

FIG. 28A is a block diagram illustrating both an exemplary in-orderpipeline and an exemplary register renaming, out-of-orderissue/execution pipeline according to embodiments of the invention. FIG.28B is a block diagram illustrating both an exemplary embodiment of anin-order architecture core and an exemplary register renaming,out-of-order issue/execution architecture core to be included in aprocessor according to embodiments of the invention. The solid linedboxes in FIGS. 28A-B illustrate the in-order pipeline and in-order core,while the optional addition of the dashed lined boxes illustrates theregister renaming, out-of-order issue/execution pipeline and core. Giventhat the in-order aspect is a subset of the out-of-order aspect, theout-of-order aspect will be described.

In FIG. 28A, a processor pipeline 2800 includes a fetch stage 2802, alength decode stage 2804, a decode stage 2806, an allocation stage 2808,a renaming stage 2810, a scheduling (also known as a dispatch or issue)stage 2812, a register read/memory read stage 2814, an execute stage2816, a write back/memory write stage 2818, an exception handling stage2822, and a commit stage 2824.

FIG. 28B shows processor core 2890 including a front end unit 2830coupled to an execution engine unit 2850, and both are coupled to amemory unit 2870. The core 2890 may be a reduced instruction setcomputing (RISC) core, a complex instruction set computing (CISC) core,a very long instruction word (VLIW) core, or a hybrid or alternativecore type. As yet another option, the core 2890 may be a special-purposecore, such as, for example, a network or communication core, compressionengine, coprocessor core, general purpose computing graphics processingunit (GPGPU) core, graphics core, or the like.

The front end unit 2830 includes a branch prediction unit 2832 coupledto an instruction cache unit 2834, which is coupled to an instructiontranslation lookaside buffer (TLB) 2836, which is coupled to aninstruction fetch unit 2838, which is coupled to a decode unit 2840. Thedecode unit 2840 (or decoder) may decode instructions, and generate asan output one or more micro-operations, micro-code entry points,microinstructions, other instructions, or other control signals, whichare decoded from, or which otherwise reflect, or are derived from, theoriginal instructions. The decode unit 2840 may be implemented usingvarious different mechanisms. Examples of suitable mechanisms include,but are not limited to, look-up tables, hardware implementations,programmable logic arrays (PLAs), microcode read only memories (ROMs),etc. In one embodiment, the core 2890 includes a microcode ROM or othermedium that stores microcode for certain macroinstructions (e.g., indecode unit 2840 or otherwise within the front end unit 2830). Thedecode unit 2840 is coupled to a rename/allocator unit 2852 in theexecution engine unit 2850.

The execution engine unit 2850 includes the rename/allocator unit 2852coupled to a retirement unit 2854 and a set of one or more schedulerunit(s) 2856. The scheduler unit(s) 2856 represents any number ofdifferent schedulers, including reservations stations, centralinstruction window, etc. The scheduler unit(s) 2856 is coupled to thephysical register file(s) unit(s) 2858. Each of the physical registerfile(s) units 2858 represents one or more physical register files,different ones of which store one or more different data types, such asscalar integer, scalar floating point, packed integer, packed floatingpoint, vector integer, vector floating point, status (e.g., aninstruction pointer that is the address of the next instruction to beexecuted), etc. In one embodiment, the physical register file(s) unit2858 comprises a vector registers unit, a write mask registers unit, anda scalar registers unit. These register units may provide architecturalvector registers, vector mask registers, and general purpose registers.The physical register file(s) unit(s) 2858 is overlapped by theretirement unit 2854 to illustrate various ways in which registerrenaming and out-of-order execution may be implemented (e.g., using areorder buffer(s) and a retirement register file(s); using a futurefile(s), a history buffer(s), and a retirement register file(s); using aregister maps and a pool of registers; etc.). The retirement unit 2854and the physical register file(s) unit(s) 2858 are coupled to theexecution cluster(s) 2860. The execution cluster(s) 2860 includes a setof one or more execution units 2862 and a set of one or more memoryaccess units 2864. The execution units 2862 may perform variousoperations (e.g., shifts, addition, subtraction, multiplication) and onvarious types of data (e.g., scalar floating point, packed integer,packed floating point, vector integer, vector floating point). Whilesome embodiments may include a number of execution units dedicated tospecific functions or sets of functions, other embodiments may includeonly one execution unit or multiple execution units that all perform allfunctions. The scheduler unit(s) 2856, physical register file(s) unit(s)2858, and execution cluster(s) 2860 are shown as being possibly pluralbecause certain embodiments create separate pipelines for certain typesof data/operations (e.g., a scalar integer pipeline, a scalar floatingpoint/packed integer/packed floating point/vector integer/vectorfloating point pipeline, and/or a memory access pipeline that each havetheir own scheduler unit, physical register file(s) unit, and/orexecution cluster—and in the case of a separate memory access pipeline,certain embodiments are implemented in which only the execution clusterof this pipeline has the memory access unit(s) 2864). It should also beunderstood that where separate pipelines are used, one or more of thesepipelines may be out-of-order issue/execution and the rest in-order.

The set of memory access units 2864 is coupled to the memory unit 2870,which includes a data TLB unit 2872 coupled to a data cache unit 2874coupled to a level 2 (L2) cache unit 2876. In one exemplary embodiment,the memory access units 2864 may include a load unit, a store addressunit, and a store data unit, each of which is coupled to the data TLBunit 2872 in the memory unit 2870. The instruction cache unit 2834 isfurther coupled to a level 2 (L2) cache unit 2876 in the memory unit2870. The L2 cache unit 2876 is coupled to one or more other levels ofcache and eventually to a main memory.

By way of example, the exemplary register renaming, out-of-orderissue/execution core architecture may implement the pipeline 2800 asfollows: 1) the instruction fetch 2838 performs the fetch and lengthdecoding stages 2802 and 2804; 2) the decode unit 2840 performs thedecode stage 2806; 3) the rename/allocator unit 2852 performs theallocation stage 2808 and renaming stage 2810; 4) the scheduler unit(s)2856 performs the schedule stage 2812; 5) the physical register file(s)unit(s) 2858 and the memory unit 2870 perform the register read/memoryread stage 2814; the execution cluster 2860 perform the execute stage2816; 6) the memory unit 2870 and the physical register file(s) unit(s)2858 perform the write back/memory write stage 2818; 7) various unitsmay be involved in the exception handling stage 2822; and 8) theretirement unit 2854 and the physical register file(s) unit(s) 2858perform the commit stage 2824.

The core 2890 may support one or more instructions sets (e.g., the x86instruction set (with some extensions that have been added with newerversions); the MIPS instruction set of MIPS Technologies of Sunnyvale,Calif.; the ARM instruction set (with optional additional extensionssuch as NEON) of ARM Holdings of Sunnyvale, Calif.), including theinstruction(s) described herein. In one embodiment, the core 2890includes logic to support a packed data instruction set extension (e.g.,AVX1, AVX2), thereby allowing the operations used by many multimediaapplications to be performed using packed data.

It should be understood that the core may support multithreading(executing two or more parallel sets of operations or threads), and maydo so in a variety of ways including time sliced multithreading,simultaneous multithreading (where a single physical core provides alogical core for each of the threads that physical core issimultaneously multithreading), or a combination thereof (e.g., timesliced fetching and decoding and simultaneous multithreading thereaftersuch as in the Intel® Hyperthreading technology).

While register renaming is described in the context of out-of-orderexecution, it should be understood that register renaming may be used inan in-order architecture. While the illustrated embodiment of theprocessor also includes separate instruction and data cache units2834/2874 and a shared L2 cache unit 2876, alternative embodiments mayhave a single internal cache for both instructions and data, such as,for example, a Level 1 (L1) internal cache, or multiple levels ofinternal cache. In some embodiments, the system may include acombination of an internal cache and an external cache that is externalto the core and/or the processor. Alternatively, all of the cache may beexternal to the core and/or the processor.

Specific Exemplary in-Order Core Architecture

FIGS. 29A-B illustrate a block diagram of a more specific exemplaryin-order core architecture, which core would be one of several logicblocks (including other cores of the same type and/or different types)in a chip. The logic blocks communicate through a high-bandwidthinterconnect network (e.g., a ring network) with some fixed functionlogic, memory I/O interfaces, and other necessary I/O logic, dependingon the application.

FIG. 29A is a block diagram of a single processor core, along with itsconnection to the on-die interconnect network 2902 and with its localsubset of the Level 2 (L2) cache 2904, according to embodiments of theinvention. In one embodiment, an instruction decoder 2900 supports thex86 instruction set with a packed data instruction set extension. An L1cache 2906 allows low-latency accesses to cache memory into the scalarand vector units. While in one embodiment (to simplify the design), ascalar unit 2908 and a vector unit 2910 use separate register sets(respectively, scalar registers 2912 and vector registers 2914) and datatransferred between them is written to memory and then read back in froma level 1 (L1) cache 2906, alternative embodiments of the invention mayuse a different approach (e.g., use a single register set or include acommunication path that allow data to be transferred between the tworegister files without being written and read back).

The local subset of the L2 cache 2904 is part of a global L2 cache thatis divided into separate local subsets, one per processor core. Eachprocessor core has a direct access path to its own local subset of theL2 cache 2904. Data read by a processor core is stored in its L2 cachesubset 2904 and can be accessed quickly, in parallel with otherprocessor cores accessing their own local L2 cache subsets. Data writtenby a processor core is stored in its own L2 cache subset 2904 and isflushed from other subsets, if necessary. The ring network ensurescoherency for shared data. The ring network is bi-directional to allowagents such as processor cores, L2 caches and other logic blocks tocommunicate with each other within the chip. Each ring data-path is1012-bits wide per direction.

FIG. 29B is an expanded view of part of the processor core in FIG. 29Aaccording to embodiments of the invention. FIG. 29B includes an L1 datacache 2906A part of the L1 cache 2904, as well as more detail regardingthe vector unit 2910 and the vector registers 2914. Specifically, thevector unit 2910 is a 16-wide vector processing unit (VPU) (see the16-wide ALU 2928), which executes one or more of integer,single-precision float, and double-precision float instructions. The VPUsupports swizzling the register inputs with swizzle unit 2920, numericconversion with numeric convert units 2922A-B, and replication withreplication unit 2924 on the memory input. Write mask registers 2926allow predicating resulting vector writes.

FIG. 30 is a block diagram of a processor 3000 that may have more thanone core, may have an integrated memory controller, and may haveintegrated graphics according to embodiments of the invention. The solidlined boxes in FIG. 30 illustrate a processor 3000 with a single core3002A, a system agent 3010, a set of one or more bus controller units3016, while the optional addition of the dashed lined boxes illustratesan alternative processor 3000 with multiple cores 3002A-N, a set of oneor more integrated memory controller unit(s) 3014 in the system agentunit 3010, and special purpose logic 3008.

Thus, different implementations of the processor 3000 may include: 1) aCPU with the special purpose logic 3008 being integrated graphics and/orscientific (throughput) logic (which may include one or more cores), andthe cores 3002A-N being one or more general purpose cores (e.g., generalpurpose in-order cores, general purpose out-of-order cores, acombination of the two); 2) a coprocessor with the cores 3002A-N being alarge number of special purpose cores intended primarily for graphicsand/or scientific (throughput); and 3) a coprocessor with the cores3002A-N being a large number of general purpose in-order cores. Thus,the processor 3000 may be a general-purpose processor, coprocessor orspecial-purpose processor, such as, for example, a network orcommunication processor, compression engine, graphics processor, GPGPU(general purpose graphics processing unit), a high-throughput manyintegrated core (MIC) coprocessor (including 30 or more cores), embeddedprocessor, or the like. The processor may be implemented on one or morechips. The processor 3000 may be a part of and/or may be implemented onone or more substrates using any of a number of process technologies,such as, for example, BiCMOS, CMOS, or NMOS.

The memory hierarchy includes one or more levels of cache within thecores, a set or one or more shared cache units 3006, and external memory(not shown) coupled to the set of integrated memory controller units3014. The set of shared cache units 3006 may include one or moremid-level caches, such as level 2 (L2), level 3 (L3), level 4 (L4), orother levels of cache, a last level cache (LLC), and/or combinationsthereof. While in one embodiment a ring based interconnect unit 3012interconnects the integrated graphics logic 3008 (integrated graphicslogic 3008 is an example of and is also referred to herein as specialpurpose logic), the set of shared cache units 3006, and the system agentunit 3010/integrated memory controller unit(s) 3014, alternativeembodiments may use any number of well-known techniques forinterconnecting such units. In one embodiment, coherency is maintainedbetween one or more cache units 3006 and cores 3002-A-N.

In some embodiments, one or more of the cores 3002A-N are capable ofmulti-threading. The system agent 3010 includes those componentscoordinating and operating cores 3002A-N. The system agent unit 3010 mayinclude for example a power control unit (PCU) and a display unit. ThePCU may be or include logic and components needed for regulating thepower state of the cores 3002A-N and the integrated graphics logic 3008.The display unit is for driving one or more externally connecteddisplays.

The cores 3002A-N may be homogenous or heterogeneous in terms ofarchitecture instruction set; that is, two or more of the cores 3002A-Nmay be capable of execution the same instruction set, while others maybe capable of executing only a subset of that instruction set or adifferent instruction set.

Exemplary Computer Architectures

FIGS. 31-34 are block diagrams of exemplary computer architectures.Other system designs and configurations known in the arts for laptops,desktops, handheld PCs, personal digital assistants, engineeringworkstations, servers, network devices, network hubs, switches, embeddedprocessors, digital signal processors (DSPs), graphics devices, videogame devices, set-top boxes, micro controllers, cell phones, portablemedia players, hand held devices, and various other electronic devices,are also suitable. In general, a huge variety of systems or electronicdevices capable of incorporating a processor and/or other executionlogic as disclosed herein are generally suitable.

Referring now to FIG. 31, shown is a block diagram of a system 3100 inaccordance with one embodiment of the present invention. The system 3100may include one or more processors 3110, 3115, which are coupled to acontroller hub 3120. In one embodiment the controller hub 3120 includesa graphics memory controller hub (GMCH) 3190 and an Input/Output Hub(IOH) 3150 (which may be on separate chips); the GMCH 3190 includesmemory and graphics controllers to which are coupled memory 3140 and acoprocessor 3145; the IOH 3150 couples input/output (I/O) devices 3160to the GMCH 3190. Alternatively, one or both of the memory and graphicscontrollers are integrated within the processor (as described herein),the memory 3140 and the coprocessor 3145 are coupled directly to theprocessor 3110, and the controller hub 3120 in a single chip with theIOH 3150.

The optional nature of additional processors 3115 is denoted in FIG. 31with broken lines. Each processor 3110, 3115 may include one or more ofthe processing cores described herein and may be some version of theprocessor 3000.

The memory 3140 may be, for example, dynamic random access memory(DRAM), phase change memory (PCM), or a combination of the two. For atleast one embodiment, the controller hub 3120 communicates with theprocessor(s) 3110, 3115 via a multi-drop bus, such as a frontside bus(FSB), point-to-point interface such as QuickPath Interconnect (QPI), orsimilar connection 3195.

In one embodiment, the coprocessor 3145 is a special-purpose processor,such as, for example, a high-throughput MIC processor, a network orcommunication processor, compression engine, graphics processor, GPGPU,embedded processor, or the like. In one embodiment, controller hub 3120may include an integrated graphics accelerator.

There can be a variety of differences between the physical resources3110, 3115 in terms of a spectrum of metrics of merit includingarchitectural, microarchitectural, thermal, power consumptioncharacteristics, and the like.

In one embodiment, the processor 3110 executes instructions that controldata processing operations of a general type. Embedded within theinstructions may be coprocessor instructions. The processor 3110recognizes these coprocessor instructions as being of a type that shouldbe executed by the attached coprocessor 3145. Accordingly, the processor3110 issues these coprocessor instructions (or control signalsrepresenting coprocessor instructions) on a coprocessor bus or otherinterconnect, to coprocessor 3145. Coprocessor(s) 3145 accept andexecute the received coprocessor instructions.

Referring now to FIG. 32, shown is a block diagram of a first morespecific exemplary system 3200 in accordance with an embodiment of thepresent invention. As shown in FIG. 32, multiprocessor system 3200 is apoint-to-point interconnect system, and includes a first processor 3270and a second processor 3280 coupled via a point-to-point interconnect3250. Each of processors 3270 and 3280 may be some version of theprocessor 3000. In one embodiment of the invention, processors 3270 and3280 are respectively processors 3110 and 3115, while coprocessor 3238is coprocessor 3145. In another embodiment, processors 3270 and 3280 arerespectively processor 3110 coprocessor 3145.

Processors 3270 and 3280 are shown including integrated memorycontroller (IMC) units 3272 and 3282, respectively. Processor 3270 alsoincludes as part of its bus controller units point-to-point (P-P)interfaces 3276 and 3278; similarly, second processor 3280 includes P-Pinterfaces 3286 and 3288. Processors 3270, 3280 may exchange informationvia a point-to-point (P-P) interface 3250 using P-P interface circuits3278, 3288. As shown in FIG. 32, IMCs 3272 and 3282 couple theprocessors to respective memories, namely a memory 3232 and a memory3234, which may be portions of main memory locally attached to therespective processors.

Processors 3270, 3280 may each exchange information with a chipset 3290via individual P-P interfaces 3252, 3254 using point to point interfacecircuits 3276, 3294, 3286, 3298. Chipset 3290 may optionally exchangeinformation with the coprocessor 3238 via a high-performance interface3292. In one embodiment, the coprocessor 3238 is a special-purposeprocessor, such as, for example, a high-throughput MIC processor, anetwork or communication processor, compression engine, graphicsprocessor, GPGPU, embedded processor, or the like.

A shared cache (not shown) may be included in either processor oroutside of both processors, yet connected with the processors via P-Pinterconnect, such that either or both processors' local cacheinformation may be stored in the shared cache if a processor is placedinto a low power mode.

Chipset 3290 may be coupled to a first bus 3216 via an interface 3296.In one embodiment, first bus 3216 may be a Peripheral ComponentInterconnect (PCI) bus, or a bus such as a PCI Express bus or anotherthird generation I/O interconnect bus, although the scope of the presentinvention is not so limited.

As shown in FIG. 32, various I/O devices 3214 may be coupled to firstbus 3216, along with a bus bridge 3218 which couples first bus 3216 to asecond bus 3220. In one embodiment, one or more additional processor(s)3215, such as coprocessors, high-throughput MIC processors, GPGPU's,accelerators (such as, e.g., graphics accelerators or digital signalprocessing (DSP) units), field programmable gate arrays, or any otherprocessor, are coupled to first bus 3216. In one embodiment, second bus3220 may be a low pin count (LPC) bus. Various devices may be coupled toa second bus 3220 including, for example, a keyboard and/or mouse 3222,communication devices 3227 and a storage unit 3228 such as a disk driveor other mass storage device which may include instructions/code anddata 3230, in one embodiment. Further, an audio I/O 3224 may be coupledto the second bus 3220. Note that other architectures are possible. Forexample, instead of the point-to-point architecture of FIG. 32, a systemmay implement a multi-drop bus or other such architecture.

Referring now to FIG. 33, shown is a block diagram of a second morespecific exemplary system 3300 in accordance with an embodiment of thepresent invention. Like elements in FIGS. 32 and 33 bear like referencenumerals, and certain aspects of FIG. 32 have been omitted from FIG. 33in order to avoid obscuring other aspects of FIG. 33.

FIG. 33 illustrates that the processors 3270, 3280 may includeintegrated memory and I/O control logic (“CL”) 3272 and 3282,respectively. Thus, the CL 3272, 3282 include integrated memorycontroller units and include I/O control logic. FIG. 33 illustrates thatnot only are the memories 3232, 3234 coupled to the CL 3272, 3282, butalso that I/O devices 3314 are also coupled to the control logic 3272,3282. Legacy I/O devices 3315 are coupled to the chipset 3290.

Referring now to FIG. 34, shown is a block diagram of a SoC 3400 inaccordance with an embodiment of the present invention. Similar elementsin FIG. 30 bear like reference numerals. Also, dashed lined boxes areoptional features on more advanced SoCs. In FIG. 34, an interconnectunit(s) 3402 is coupled to: an application processor 3410 which includesa set of one or more cores 3002A-N, which include cache units 3004A-N,and shared cache unit(s) 3006; a system agent unit 3010; a buscontroller unit(s) 3016; an integrated memory controller unit(s) 3014; aset or one or more coprocessors 3420 which may include integratedgraphics logic, an image processor, an audio processor, and a videoprocessor; an static random access memory (SRAM) unit 3430; a directmemory access (DMA) unit 3432; and a display unit 3440 for coupling toone or more external displays. In one embodiment, the coprocessor(s)3420 include a special-purpose processor, such as, for example, anetwork or communication processor, compression engine, GPGPU, ahigh-throughput MIC processor, embedded processor, or the like.

Embodiments of the mechanisms disclosed herein may be implemented inhardware, software, firmware, or a combination of such implementationapproaches. Embodiments of the invention may be implemented as computerprograms or program code executing on programmable systems comprising atleast one processor, a storage system (including volatile andnon-volatile memory and/or storage elements), at least one input device,and at least one output device.

Program code, such as code 3230 illustrated in FIG. 32, may be appliedto input instructions to perform the functions described herein andgenerate output information. The output information may be applied toone or more output devices, in known fashion. For purposes of thisapplication, a processing system includes any system that has aprocessor, such as, for example; a digital signal processor (DSP), amicrocontroller, an application specific integrated circuit (ASIC), or amicroprocessor.

The program code may be implemented in a high level procedural or objectoriented programming language to communicate with a processing system.The program code may also be implemented in assembly or machinelanguage, if desired. In fact, the mechanisms described herein are notlimited in scope to any particular programming language. In any case,the language may be a compiled or interpreted language.

One or more aspects of at least one embodiment may be implemented byrepresentative instructions stored on a machine-readable medium whichrepresents various logic within the processor, which when read by amachine causes the machine to fabricate logic to perform the techniquesdescribed herein. Such representations, known as “IP cores” may bestored on a tangible, machine readable medium and supplied to variouscustomers or manufacturing facilities to load into the fabricationmachines that actually make the logic or processor.

Such machine-readable storage media may include, without limitation,non-transitory, tangible arrangements of articles manufactured or formedby a machine or device, including storage media such as hard disks, anyother type of disk including floppy disks, optical disks, compact diskread-only memories (CD-ROMs), compact disk rewritable's (CD-RWs), andmagneto-optical disks, semiconductor devices such as read-only memories(ROMs), random access memories (RAMs) such as dynamic random accessmemories (DRAMs), static random access memories (SRAMs), erasableprogrammable read-only memories (EPROMs), flash memories, electricallyerasable programmable read-only memories (EEPROMs), phase change memory(PCM), magnetic or optical cards, or any other type of media suitablefor storing electronic instructions.

Accordingly, embodiments of the invention also include non-transitory,tangible machine-readable media containing instructions or containingdesign data, such as Hardware Description Language (HDL), which definesstructures, circuits, apparatuses, processors and/or system featuresdescribed herein. Such embodiments may also be referred to as programproducts.

Emulation (Including Binary Translation, Code Morphing, Etc.)

In some cases, an instruction converter may be used to convert aninstruction from a source instruction set to a target instruction set.For example, the instruction converter may translate (e.g., using staticbinary translation, dynamic binary translation including dynamiccompilation), morph, emulate, or otherwise convert an instruction to oneor more other instructions to be processed by the core. The instructionconverter may be implemented in software, hardware, firmware, or acombination thereof. The instruction converter may be on processor, offprocessor, or part on and part off processor.

FIG. 35 is a block diagram contrasting the use of a software instructionconverter to convert binary instructions in a source instruction set tobinary instructions in a target instruction set according to embodimentsof the invention. In the illustrated embodiment, the instructionconverter is a software instruction converter, although alternativelythe instruction converter may be implemented in software, firmware,hardware, or various combinations thereof. FIG. 35 shows a program in ahigh level language 3502 may be compiled using an x86 compiler 3504 togenerate x86 binary code 3506 that may be natively executed by aprocessor with at least one x86 instruction set core 3516. The processorwith at least one x86 instruction set core 3516 represents any processorthat can perform substantially the same functions as an Intel processorwith at least one x86 instruction set core by compatibly executing orotherwise processing (1) a substantial portion of the instruction set ofthe Intel x86 instruction set core or (2) object code versions ofapplications or other software targeted to run on an Intel processorwith at least one x86 instruction set core, in order to achievesubstantially the same result as an Intel processor with at least onex86 instruction set core. The x86 compiler 3504 represents a compilerthat is operable to generate x86 binary code 3506 (e.g., object code)that can, with or without additional linkage processing, be executed onthe processor with at least one x86 instruction set core 3516.Similarly, FIG. 35 shows the program in the high level language 3502 maybe compiled using an alternative instruction set compiler 3508 togenerate alternative instruction set binary code 3510 that may benatively executed by a processor without at least one x86 instructionset core 3514 (e.g., a processor with cores that execute the MIPSinstruction set of MIPS Technologies of Sunnyvale, Calif. and/or thatexecute the ARM instruction set of ARM Holdings of Sunnyvale, Calif.).The instruction converter 3512 is used to convert the x86 binary code3506 into code that may be natively executed by the processor without anx86 instruction set core 3514. This converted code is not likely to bethe same as the alternative instruction set binary code 3510 because aninstruction converter capable of this is difficult to make; however, theconverted code will accomplish the general operation and be made up ofinstructions from the alternative instruction set. Thus, the instructionconverter 3512 represents software, firmware, hardware, or a combinationthereof that, through emulation, simulation or any other process, allowsa processor or other electronic device that does not have an x86instruction set processor or core to execute the x86 binary code 3506.

What is claimed is:
 1. A processor comprising: a matrix operationsaccelerator circuit comprising a two-dimensional grid of fused multiplyaccumulate circuits; a first plurality of registers, that represents atleast one two-dimensional destination matrix, coupled to the matrixoperations accelerator circuit; decode circuitry to decode a matrix pairzeroing instruction having fields to specify an opcode and the at leastone two-dimensional destination matrix; and execution circuitry toexecute the decoded matrix pair zeroing instruction per the opcode tozero every element of a pair of destination matrices of the at least onetwo-dimensional destination matrix in response to a status register forthe at least one two-dimensional destination matrix having a first fieldset to indicate the at least one two-dimensional destination matrix isvalid and a second field set to indicate the at least onetwo-dimensional destination matrix comprises the pair of destinationmatrices.
 2. The processor of claim 1, wherein the opcode defines a sizeof each data element of the pair of destination matrices.
 3. Theprocessor of claim 2, wherein the size of each data element of the pairof destination matrices is a doubleword.
 4. The processor of claim 2,wherein the size of each data element of the pair of destinationmatrices is a word.
 5. The processor of claim 1, wherein the executioncircuitry is further to execute the decoded matrix pair zeroinginstruction to zero any data elements in remaining columns and rows ofthe at least one two-dimensional destination matrix when zeroing theelements of the pair of destination matrices.
 6. The processor of claim1, wherein the execution circuitry is to fault, for execution of thedecoded matrix pair zeroing instruction, upon a determination that thesecond field is not set to indicate the at least one two-dimensionaldestination matrix comprises the pair of destination matrices.
 7. Amethod comprising: decoding, with decode circuitry of a hardwareprocessor core coupled to a matrix operations accelerator circuitcomprising a two-dimensional grid of fused multiply accumulate circuits,the matrix operations accelerator circuit coupled to a first pluralityof registers that represents at least one two-dimensional destinationmatrix, a matrix pair zeroing instruction specifying an opcode and theat least one two-dimensional destination matrix; and executing, withexecution circuitry of the hardware processor core, the decoded matrixpair zeroing instruction per the opcode to zero every element of a pairof destination matrices of the at least one two-dimensional destinationmatrix in response to a status register for the at least onetwo-dimensional destination matrix having a first field set to indicatethe at least one two-dimensional destination matrix is valid and asecond field set to indicate the at least one two-dimensionaldestination matrix comprises the pair of destination matrices.
 8. Themethod of claim 7, wherein the opcode specifies a size of each dataelement of the pair of destination matrices.
 9. The method of claim 8,wherein the size of each data element of the pair of destinationmatrices is a doubleword.
 10. The method of claim 8, wherein the size ofeach data element of the pair of destination matrices is a word.
 11. Themethod of claim 7, wherein the executing the decoded matrix pair zeroinginstruction further comprises zeroing any data elements in remainingcolumns and rows of the at least one two-dimensional destination matrixwhen zeroing the elements of the pair of destination matrices.
 12. Themethod of claim 7, wherein the executing the decoded matrix pair zeroinginstruction further comprises faulting upon a determination that thesecond field is not set to indicate the at least one two-dimensionaldestination matrix comprises the pair of destination matrices.
 13. Anon-transitory machine-readable medium storing code that when executedby a machine causes the machine to perform a method comprising:decoding, with decode circuitry of a hardware processor core coupled toa matrix operations accelerator circuit comprising a two-dimensionalgrid of fused multiply accumulate circuits, the matrix operationsaccelerator circuit coupled to a first plurality of registers thatrepresents at least one two-dimensional destination matrix, a matrixpair zeroing instruction specifying an opcode and the at least onetwo-dimensional destination matrix; and executing, with executioncircuitry of the hardware processor core, the decoded matrix pairzeroing instruction per the opcode to zero every element of a pair ofdestination matrices of the at least one two-dimensional destinationmatrix in response to a status register for the at least onetwo-dimensional destination matrix having a first field set to indicatethe at least one two-dimensional destination matrix is valid and asecond field set to indicate the at least one two-dimensionaldestination matrix comprises the pair of destination matrices.
 14. Thenon-transitory machine-readable medium of claim 13, wherein the opcodedefines a size of each data element of the pair of destination matrices.15. The non-transitory machine-readable medium of claim 13, wherein theexecuting the decoded matrix pair zeroing instruction further compriseszeroing any data elements in remaining columns and rows of the at leastone two-dimensional destination matrix when zeroing the elements of thepair of destination matrices.
 16. The processor of claim 1, wherein theexecution circuitry is to operate on one row of the at least onetwo-dimensional destination matrix at a time, starting with a first row.17. The processor of claim 1, wherein the execution circuitry is tooperate on one chunk of C bytes at a time of a row being operated on, Cbeing a positive integer ranging between 1 byte and a whole row ofbytes.
 18. The method of claim 7, wherein the executing is performed inparallel on one row of elements of the at least one two-dimensionaldestination matrix at a time, starting with a first row.
 19. The methodof claim 7, wherein the executing is performed in parallel on one chunkof C bytes at a time of a row being operated on, C being a positiveinteger ranging between 1 byte and a whole row of bytes.
 20. Theprocessor of claim 6, wherein the execution circuitry is to fault, forexecution of the decoded matrix pair zeroing instruction, upon adetermination that the first field is not set to indicate the at leastone two-dimensional destination matrix is valid.
 21. The method of claim12, wherein the executing the decoded matrix pair zeroing instructionfurther comprises faulting upon a determination that the first field isnot set to indicate the at least one two-dimensional destination matrixis valid.
 22. The non-transitory machine-readable medium of claim 13,wherein the executing the decoded matrix pair zeroing instructionfurther comprises faulting upon a determination that the second field isnot set to indicate the at least one two-dimensional destination matrixcomprises the pair of destination matrices.
 23. A system comprising: amatrix operations accelerator circuit comprising: a two-dimensional gridof fused multiply accumulate circuits, and a first plurality ofregisters, that represents at least one two-dimensional destinationmatrix, coupled to the two-dimensional grid of fused multiply accumulatecircuits; and a hardware processor coupled to the matrix operationsaccelerator circuit, the hardware processor comprising: decode circuitryto decode a matrix pair zeroing instruction having fields to specify anopcode and the at least one two-dimensional destination matrix, andexecution circuitry to execute the decoded matrix pair zeroinginstruction per the opcode to zero every element of a pair ofdestination matrices of the at least one two-dimensional destinationmatrix in response to a status register for the at least onetwo-dimensional destination matrix having a first field set to indicatethe at least one two-dimensional destination matrix is valid and asecond field set to indicate the at least one two-dimensionaldestination matrix comprises the pair of destination matrices.
 24. Thesystem of claim 23, wherein the execution circuitry is to operate on onerow of the at least one two-dimensional destination matrix at a time,starting with a first row.
 25. The system of claim 23, wherein theexecution circuitry is to operate on one chunk of C bytes at a time of arow being operated on, C being a positive integer ranging between 1 byteand a whole row of bytes.